Sex, Viruses and Grief

Sex, Viruses and Grief: A Deadly Combination That Poses The Greatest Threat To Human Health In The Twenty-First Century

An Inaugural Lecture

Presented By

Nana K. Ayisi, DVM,PhD Professor & Head Virology Unit, NMIMR, University of Ghana

Mr. Vice-Chancellor, distinguished guests, to my knowledge, this Inaugural Lecture is the first from the Noguchi Memorial Institute for Medical Research (NMIMR). It is also the first in Medical Virology at this university. It is certainly not the first in Pharmacology but unique in the sense that it combines Pharmacology, Toxicopathology, Virology, and Medicine. For obvious reasons, I would like to begin this lecture by touching on the importance of zoonotic viral diseases to the field of infectious diseases.

The world experienced the swine flu epidemic in 1918 that killed more than 20 million people and is now known to have been caused by a mutation that evolved in US pigs and was spread around the globe by US troops mobilized for the first World War. We have recently experienced the severe acute respiratory syndrome (SARS) scare which involved the transmission of a corona virus from rodents to man. We have also become aware of the bird flu in South East Asia that luckily did not involve the pig as an intermediary host.

Most experts believe that the human flu viruses reside harmlessly in birds. When a bird flu virus infects pigs, the immune system of the pigs attacks the virus. The virus mutates in order to survive. The new flu virus when transmitted from pigs to man causes devastating illness. We are presently confronted with the dreaded human immunodeficiency virus (HIV) which is believed to have been transmitted to man from nonhuman primates.

The fact that the primary mode of HIV infection is by sexual transmission, has brought about contentious debates of religious, traditional, and socioeconomic dimensions to the field of infectious diseases. We should thank our creator that the mode of transmission of this virus is different from that of the flu virus. It is obvious that the emergence of HIV was not intended to wipe out mankind otherwise aerosol would have been the preferred mode of transmission. Perhaps HIV chose the sexual route of transmission in order to teach us some lessons about sexual behaviour and sanctity of sexual intercourse.

As a trained Veterinary Surgeon, my research and teaching career have been multidisciplinary and this inaugural lecture will reflect that diverse background. I would hope to demonstrate my long-term commitment to research in the treatment and prevention of sexually transmitted viral infections by delivering this Inaugural Lecture on the topic "Sex, Viruses and Grief: A Deadly Combination That Poses The Greatest Threat To Human Health In The Twenty-First Century".

The female genital tract is familiar to all of us except the few who were delivered by caesarian section and those who have chosen celibacy as a way of life. This organ and its male counterpart are a source of pleasure in adulthood. They are also a source of discomfort and grief for those who overuse or misuse them. Sexual intercourse has become a medium for the transmission of some of the most important viruses that cause severe morbidity and mortality in humans.

Important sexually transmitted viruses include herpes simplex virus type 2 (HSV-2), human cytomegalovirus (HCMV), hepatitis B and C viruses (HBV and HCV), human papilomavirus (HPV), and the dreaded human immunodeficiency virus (HIV). Of all the sexually transmitted viral infections, HIV is the one that carries with it the most serious social stigma. HIV-2 was the predominant type in Ghana until the mid-1990s when HIV-1 took over.

Next to HIV in social importance is herpes simplex virus (HSV) infections. For centuries, HSV-1 infections were of major concern prompting the Roman emperor Tiberius to ban kissing in public some two thousand years ago. In the 1960s, Western society experienced a sexual revolution that brought genital herpes to the forefront of medical research in infectious diseases. Prior to the sexual revolution, HSV-1 infection was restricted to the waist up whereas HSV-2 infection was restricted to the waist down. With the practice of oral sex, we now find substantial cases of HSV-1 at waist down and HSV-2 at waist up.

Viruses are obligate parasites with no known beneficial attributes to man. Viruses in general and sexually transmitted viruses in particular pose special problems to mankind since they are very difficult to control. The herpes simplex viruses especially are ubiquitous in nature and cause a range of infections from mild cold sores to severe genital herpes and encephalitis. The HSV does not cause congenital malformations. However, another herpes virus, HCMV, can cause serious congenital malformations in the fetus. With the advent of HIV, HCMV has gained prominence as a possible cofactor for infection as well as causing serious pulmonary and ocular infections in AIDS patients. HSV type 2 induced genital lesions are also believed to facilitate HIV infection. HBV and HCV are involved in serious hepatic diseases. HPV is suspected to be the main causative agent for cervical cancer. HIV of course is the causative agent for acquired immunodeficiency syndrome (AIDS). With the exception of HPV, there are treatments for all the sexually transmitted viruses even though in certain cases, the treatments may not be complete. My career research work has focused on the treatment and prevention of genital HSV and HIV infections.

When HSV first infects the vaginal epithelium, there is virus replication with subsequent vesicle formation, inflammation, sores, and healing. The virus then travels along autonomic verve fibers to the dorsal root ganglia after causing lesions or in some cases may do so without causing lesions. The first clinical episode is called primary genital HSV infection and this can be very severe and excruciatingly painful whereas recurrent genital HSV infection is usually mild or asymptomatic. Children born to mothers who are shedding the virus, can acquire the infection during child birth. It is therefore advisable to take vaginal swabs for virus isolation during the last trimester of pregnancy so that caesarian delivery can be performed for those who are positive shedders.

HSV recurrence takes place when the immune system is depressed or when the body is under some form of stress. It is the usual spoiler in anticipated perfect dates. Many stories have been told of how genital HSV recurrence breaks out in women a day or so before expected dates with their ideal men. The anxiety somehow activates the virus to come out from the dorsal root ganglia to cause genital lesions that eventually spoil the dates. Because this virus travels along autonomic nerve fibers, it is able to avoid the effects of the hormonal immune system.

Mr. Vice-Chancellor, distinguished guests, I would like to take you on a short journey through my academic and research career culminating in my present position as Professor of Pharmacology and Microbiology.

Despite obtaining a Ghana Government Scholarship to study Veterinary Medicine at Tuskegee University, I was initially not fully committed to that field until I went through professional orientation and realized that I had career options other than being confined to routine clinical work. Research was right from the beginning at the heart of my career dreams.

As a veterinary medical student, my two major electives were in Microbiology and Physiology. In Microbiology, I worked on Immunological and Pathological Studies on Salmonella typhimirium in rats. In Physiology, I worked on the Pathophysiology of Surgically Induced Congestive Heart Failure in the dog.

As a committed nationalist, patriot, and Pan-Africanist, I headed home soon after obtaining my DVM. Three years clinical and administrative work as a Veterinary Officer was enough for me. The Western College of Veterinary Medicine, University of Saskatchewan, Canada, offered me a choice between Postgraduate Pathology and Postgraduate Pharmacology/Toxicology. I chose Pharmacology/Toxicology because of the attractive new field of Antiviral Chemotherapy that was available at that time.

In the mid-1970s, Prof. V. S. Gupta and collaborators had synthesized a nucleoside analog known as 5-methoxymethyl-2'-deoxyuridine (MMUdR) as a possible inhibitor of the virus that causes infectious bovine rhinotracheitis (IBR). IBR is a serious respiratory disease of cattle in North America caused by a herpes virus. When MMUdR failed to inhibit IBR, it was thought that it would be prudent to test this compound against HSV. The results were excellent and thus began the Anti-HSV Chemotherapy Research at the University of Saskatchewan.

Herpes simplex viruses present with unique targets that lend themselves to differential inhibition by nucleoside analogs. The two most important targets are (1) viral induced thymidine-deoxycytidine/thymidylate kinase and (2) viral induced DNA polymerase. HSV induced TK has been the main target for drug development. Viral induced thymidine kinase catalyses the conversion of thymidine to thymidine monophosphate and diphosphate. Further phosphorylation by host cell enzyme, leads to thymidine triphosphate which is then incorporated into DNA by DNA polymerase. Both HSV-1 and HSV-2 induced dT kinases possess a lower pH optimum and a lower Km (thus a higher substrate affinity) than the corresponding host cell enzymes. They are more heat stable than the respective host cell enzymes and also more resistant to feedback inhibition by dTTP and dCTP.

Why would the HSV induce its own enzymes? One reason is that by inducing intermediary nucleoside metabolic enzymes with Km values less than those of host cells, the virus obviously would have an advantage in the utilization of thymidine. In other words, the virus would replicate faster than the host cells. The other reason is that the Almighty God created solutions for every problem He/She created. The biochemical differences in virus-induced and host cell enzymes, were created by the Almighty God for man to exploit in developing treatments for HSV.

5-Methoxymethyl-2'-deoxyuridine (MMUdR), 9-(2-hydroxyethoxymethyl)guanine (acyclovir, acycloguanosine) and other selective inhibitors of HSV replication, were synthesized to take advantage of the biochemical differences in virus induced enzymes and host cell enzymes to be effective as drugs. These drugs are preferentially phosphorylated by HSV induced thymidine kinase and thus are activated mainly in virus infected cells. They therefore have very little effects on host cells making them safe for treating HSV infections. Despite the selectivity of action of these nucleoside analogs, the herpes simplex viruses seem to be prepared for a contest of win or loose. I have always maintained that the herpes simplex virus has a mind of its own. It has developed strategies to avoid the effects of nucleoside analogs. Some clinical isolates of the virus do not induce thymidine kinase at all. Other clinical isolates induce altered thymidine kinase that cannot be competitively inhibited by nucleoside analogs. In the presence of nucleoside analogs, the HSV readily develops drug resistance. The virus also has adopted the skin as its major host organ for disease causation. The skin fibroblasts (including perivaginal skin) contain nucleoside phosphorylase, an enzyme that catalyses the splitting of the sugar from the base of nucleosides thus pharmacokinetically yielding non-active products. The herpes simplex viruses also establish latency in the trigeminal and dorsal root ganglia where they are not affected by therapy. Man has not been able to completely overcome the pharmacodynamic challenges of natural and acquired drug resistance. The pharmacokinetics problem of instability of nucleoside analogs in vivo has been overcome by the development of acyclic nucleosides like acyclovir. The problem of viral latency is still with us today.

At the University of Saskatchewan, our program was to develop a drug combination that would be more effective than the single components and also be able to reduce the emergence of drug resistance strains. Several nucleoside analog combinations were tested using dose and response isobolograms. The combination of 5-methoxymethyl-2'-deoxyuridine (MMUdR) and arabinosyl-adenine (ara-A) was found to produce the best synergistic interaction against herpes simplex viruses. This synergistic interaction was irrespective of virus strain used and was also effective in reducing the emergence of drug resistance.

In mice and guinea pig genital herpes models, the combination was far more effective than single drugs in preventing disease progression. Using dissecting microscope, the dorsal root ganglia were removed and explanted in Vero cells. It was shown that the drug combination was able to prevent establishment of HSV latency. It must however be noted that this is of very little clinical significance since in clinical genital herpes infection, the virus would have been already established in the dorsal root ganglia.

Further studies on MMUdR showed that this drug has favourable pharmacokinetics. In acute and subacute toxicity studies in rats, only mild liver lesions were seen at very high doses. Mutagenicity tests in sister chromatid exchanges and hypoxathine-guanine phosphoribosyl transferase assays showed that MMUdR is not mutagenic. MMUdR was eventually sold to an Investment Company for two million dollars ($2,000,000).

In December 1982, I joined the Antiviral Chemotherapy Group at the Division of Infectious Diseases, Department of Medicine, University of British Columbia to work on another nucleoside analog known as 5-Bromovinyl-2'-deoxyuridine (BVDU).

BVDU was originally synthesized by Dr. Dieter Barwolf and his group in East Germany. Its anti-HSV activities were discovered by Prof. Erik De Clercq and his group at the Rega Institute for Medical Research, Katholiek University of Leuven, Belgium. BVDU is the most active anti-HSV drug synthesized to date. The in vivo efficacy was however far less than was expected. In addition, BVDU like all other nucleoside analogs, showed better activities against HSV-1 than against HSV-2. A program was therefore designed to unravel the reasons for these findings.

The Antiviral Research Group at the University of British Columbia and that at the Katholiek University of Leuven decided to collaborate on pharmacokinetic studies as a means of elucidating nucleoside analog effects on HSV in vivo. At that time, there was no information on the high performance liquid chromatographic (HPLC) conditions for detecting BVDU and its metabolites.

After several months of intensive work, the HPLC conditions were established and it became practicable to investigate the pharmacokinetic basis for differential activity of BVDU against HSV-1 and HSV-2 and the less than expected in vivo efficacy. It was discovered that HSV-1 induced TK is able to metabolize BVDU to the monophosphate and diphosphate derivatives whereas the HSV-2 induced TK metabolized BVDU to only the monophosphate derivative. Thus the differential activity of BVDU against HSV-1 and HSV-2 is explained by the differential activities of the TK enzymes induced by these two types of HSV. This finding may pertain to all other nucleoside analogs since all clinically useful ones are far more effective against HSV-1 than HSV-2. The unexpected low in vivo efficacy of BVDU was found to be due to its breakdown by nucleoside phosphorylase.

I returned to Ghana in 1989 with the hope of continuing my work on antiviral chemotherapy. The possibility of continuing the Antiviral Chemotherapy work in Ghana was hampered by lack of resources. At the time I joined NMIMR, this field of work was not part of the JICA supported programs. Through the kindness of Prof. Masanori Hayami of Kyoto University, I was able to start some anti-HSV work.

As HIV became more important in infectious diseases research it was just a matter of time before that virus became the main focus of my research. The opportunity came when I was offered a visiting Associate Professorship by the University of Saskatchewan to help develop an anti-HIV drug program. At that time, Professor Gupta and his group had synthesized a number of nucleoside analogs that were intended as inhibitors of HIV. We were able to modify the tetrazolium-based colorimetric assay to take into account the independent effects of the drugs themselves on the host cells.

The original method was developed by Prof. Erik De Clercq and his group in Belgium. We derived a new formula for calculating the percent drug protection of cells from HIV cytopathicity. Our work was published in the Journal of Virological Methods, the same journal in which Prof. De Clercq and his group published their original work. After three months in Canada, I returned to Ghana with two strains of HIV-1 and two cell lines.

Please note that despite the much heralded news of isolation of HIV at Noguchi, there was no live virus in the institute at that time. The HIV strains I brought from Canada were used to begin the first HIV cultures in Ghana. This was in 1990 when it was all over in the news that Nana Drobo had discovered a cure for AIDS. I was encouraged by this news to switch from synthetic compounds to natural products, particularly, plant products as possible sources for antiviral drugs.

For centuries, natural products, especially medicinal plant products, have been used by our ancestors for the treatment of various ailments. In Africa, mystic ideas and stories have evolved around the practice of medicinal plants use. With time, the local scientific knowledge about medicinal plants, has become shrouded in secrecy and as a result, fetish priests have come to dominate this practice.

Africa is naturally endowed with thousands of medicinal plants and yet has not been able to develop them into usable forms for acceptance into mainstream medical practice. The road of natural products-to-drugs is a very tedious one that is time consuming and capital intensive.

The Noguchi Memorial Institute for Medical Research (NMIMR) has discovered a number of plants with anti-HIV and anti-HSV activities and the findings on HIV have been confirmed by the US National Institutes of Health (NIH). The mention of usage of medicinal plants in clinical practice usually brings about intense debates between traditional medical practitioners and orthodox medical practitioners. This type of contention is unnecessary since both types of practice have contributed to the development of many of the drugs we use in our clinics today.

Let me use the example of curare to demonstrate this point. The South American Indians used extracts from the plant Chondodendron tomentosum on their arrow heads to immobilize animals and capture them for food. They ate the meat of the captured animals with impunity. They knew that they would not suffer the same fate as the animals they had captured. In other words, they knew that they could not be immobilized if they ate the meat. Obviously, the South American Indians found out that extracts of Chondodendron tomentosum are very poorly absorbed from the oral route. Orthodox medical science identified the active compound in Chondodendron tomentosum to be d-tubocurarine. D-tubocurarine turned out to be a quaternary ammonium compound. Quaternary ammonium compounds were later on found to be highly ionized under physiological conditions and therefore very poorly pass biological membranes. This is the simple reason why the South American Indians were not immobilized when they ate the poisoned meats. Through orthodox scientific research, d-tubocurarine is now used as a muscle relaxant. Thus it took the contributions of both traditional plant research and orthodox scientific research to bring d-tubocurarine, a natural product derived from the plant Chondodendron tomentosum, into mainstream medical practice.

It is a nightmare for mainstream medical practitioners when they have to administer orthodox drugs to patients who have been on herbal medicine. Such herbal medicines may have induced or suppressed liver microsomal drug metabolizing enzymes. The result is a decrease or an increase in the action of the administered orthodox drug thus altering the therapeutic response. This is even worse when the drug-medicinal plant interaction affects protein binding. The result in that case would be toxicity of an otherwise nontoxic drug. Thus proper research on claimed medicinal plants is needed in order to bring them into mainstream medical practice. With the new knowledge in anti-HIV work acquired from Canada, I was poised to help investigate and develop the claims by Nana Drobo.

The first contact was made by the secretary of Nana Drobo. Apparently, some HIV positive patients at Nwoase had mentioned NMIMR to Nana Drobo. A visit to Nwoase was planned and took place in early 1991. The Noguchi delegation included most of the staff in the Virology Unit and two Japanese scientists who were on a working visit to Noguchi at that time. A general meeting was held with Nana Drobo who briefed the delegation on general activities at his shrine. He was then presented with gifts by the Noguchi staff and the Japanese visitors. Nana Drobo then requested for a private meeting with me. In attendance was his secretary. What transpired was a revelation of a man, who despite not having formal scientific training, was esteemed in some aspects of scientific knowledge. The discovery of the claimed anti-HIV plants by Nana Drobo was based on scientific principles.

Let me for the very first time reveal that secret. For those of you who work in the areas of anticancer and antiviral chemotherapy, you must be aware of the similarities in therapeutic approaches in the two areas. Iodoxyuridine, for example, was originally synthesized as an anticancer drug but has ended up as an antiviral drug for the treatment of herpes simplex virus keratitis. Arabinosyl-cytosine was originally synthesized as an antiviral drug but has ended up as the single most effective drug for the induction of remission in acute myelocytic leukemia. It turned out that Nana Drobo selected his plants for treating HIV/AIDS patients based on the claimed fact that the plants had been found to inhibit cancer cells by a relative of his in the USA. If this is true, then Nana Drobo may have been one of the first people to have tested an anticancer agent for its possible anti-AIDS efficacy.

At the meeting with Nana Drobo, he was briefed on the processes that would be followed in the event he decided to let Noguchi work on his claimed discovery. He was informed that before Noguchi starts any work on his plants, a legal agreement would have to be signed. He agreed and promised to send his secretary and lawyer to Noguchi for further discussions. The appointed day went by without any sign of them at Noguchi only to have his secretary appear on GTV that evening to tell the country that the Kwame Nkrumah University of Science and Technology (KNUST) was going to research into the claims by Nana Drobo. This turn of events was later on followed by a report in the daily papers of a committee/board set up by the Ghana Medical Association to investigate the validity of Nana Drobo's claim. With all due respect, this was a totally wrong approach. As Noguchi became sidelined in the whole affair, it became clear to some of us that no immediate answers would be found for the claims by Nana Drobo.

The whole issue took a new twist when a Japanese colleague informed me that a delegation from Japan would come to Ghana to make arrangements for testing Nana Drobo's plants. I was to lead the delegation to Nana Drobo as well as give a televised interview on the subject to the Japanese television crew accompanying the delegation. The Japanese colleague who gave my name to the delegation obviously did not know that Nana Drobo had broken all contacts with Noguchi. On their arrival, the delegation visited Noguchi to request for the said interview. I discussed their request with the director of Noguchi who advised that in view of the fact that Nana Drobo had abandoned Noguchi for KNUST, I should not grant the interview, although eventually the director ended up giving an interview on the said subject to the delegation and this was televised on Japanese television. In the final analysis, all these events might have confused Nana Drobo as to whether there were really competent scientists in Ghana to work on his claimed discovery. Nana Drobo is partly to be blamed for not being faithful to the original arrangements I made with him regarding the involvement of Noguchi. As to whether Nana Drobo's plants really had anti-HIV/AIDS activities or not, no one will ever know since he is no longer with us.

Fellow countrymen and women, have we as a nation learnt any lessons from the tragic case of Nana Drobo? What are our plans for preclinical and clinical development of claimed anti-HIV medicinal plants? We can choose to do step-by-step preclinical research before clinical trials and thus bring these medicinal plants into mainstream medical practice. On the other hand, we can choose to pursue the currently popular but IRRESPONSIBLE approach of clinical trials without proper prior preclinical studies and thus condemn the use of medicinal plants to a field outside mainstream medical practice.

Big pharmaceutical companies are making millions of dollars on a single effective drug. Some of these same companies are spending large amounts of money to do research on medicinal plants. As a country endowed with such natural products and natives who have used these plants for centuries, we owe it to ourselves, to our country and children unborn, to devote more financial and human resources to their development. Time is, however, running out. We are loosing the rich forests along with the plants in them and the people with the rich knowledge of medicinal plants are dying. The latter is of primary concern since most of the knowledge is passed on orally with hardly any written records.

The knowledge on effective traditional medicinal plants is critical for reducing the number of plants to be screened and this will make the process of developing potential medicinal plants more efficient. It is not an exaggeration to say that a single medicinal plant that is moved into mainstream medical practice has the potential to pay for the entire health budget of the nation and make the cash and carry system redundant. In fact an investment in the development of Ghanaian medicinal plants will be the best health insurance for the people of this country.

With this in mind, let us get back to the discovery of anti-HSV and anti-HIV plants at Noguchi. With the disappointing turn of events surrounding Nana Drobo's claims, I decided to take my annual leave and go to Larteh-Akuapem to interview herbalists and collect anti-infective plant products. As I was closing my office door to go, a middle-aged man walked to me with a polythene bag containing various plants. I recognized this gentleman as a patient who had come to me sometime ago with a mysterious ailment. He offered the plants to me and told me that some had been used in his family for many generations as anti-HSV products and others were randomly picked by him. He offered the plants to me without asking for anything in return. He told me that the offer was his way of thanking me for all the help I had given him in trying to diagnose his ailment. The annual leave was abandoned and I set out to test the plants for anti-HSV and anti-HIV activities.

I have earlier on dealt with the pathogenicity of HSV-2 to explain problems in infection and suggest approaches for treatment and prevention. HIV infection is even more complex. Like HSV-2, the primary route of infection for HIV is through sexual intercourse.

Women are at higher risk for HIV infection since the vagina serves as a reservoir for infected seminal fluids and the infected macrophages they contain. HIV infects CD4+ T-lymphocytes and macrophages. The infection starts with attachment of the gp120 molecule on the virus membrane to the CD4 receptor on the host cell membrane. This attachment is facilitated by CCR5 co-receptors of T-lymphocytes and CXCR4 co-receptors on macrophages. After attachment, there is fusion of virus membrane with host cell membrane and the virus enters the cell.

CD4-independent sexual transmission is also now known to occur even though to a far less extent than CD4-dependent sexual transmission. The infection can also be by cell-associated or cell-free virions. Both lymphocyte-tropic and macrophage-tropic strains of HIV can be transmitted sexually.

After infection, there is active replication of the virus mediated by viral associated reverse transcriptase even though antibodies production may not be detected for nearly 9 months. As a lentivirus, HIV establishes latency in the nucleus of infected cells. Some of these cells may serve as minute factories churning out millions of virus particles without the cells undergoing lytic infection.

Contrary to earlier speculations, the immune system puts up a very heroic fight against HIV and the onset of AIDS is an indication that the immune system has lost the fight. The situation is even made worse by the fact that HIV can establish latency in the cells they infect and lie dormant for the right conditions to cause disease.

The fact that the virus mutates rapidly also mitigates against the possibility of developing a vaccine that will be effective against all the possible mutants. The problems itemized for vaccine use also pertain to drug use as a cure.

When we talk of cure for HIV infection, we are reminded of the numerous adverts that keep on saturating our airwaves about ridiculous claims of cures by herbalists in this country. Ghana has recently embarked on treatment programs for HIV using combinations of available nucleoside RT inhibitors, non-nucleoside RT inhibitors and protease inhibitors. It must be emphasized here that in view of the long-lived pool of resting CD4+ lymphocytes cells that harbour replication-competent HIV, it may take more than 100 years of complete control of viral replication with therapy in order to eradicate these cells and effect a cure. Discontinuing efficacious antiretroviral therapy after years of apparently complete response would invariably lead to relapse of viremia.

The situation is made more uncertain by the fact that unlike in North America and Europe where the predominant HIV-1 subtype is B, the HIV-1 subtype in West-Africa is AG (a mosaic of subtypes A and G) now called CRF02_AG. We therefore need more research on the in vitro activities of the available drugs against subtype CRF02_AG in order to be able to choose the appropriate combination regimens for our local use.

Furthermore, the fitness of drug resistant mutants of subtype CRF02_AG strains needs to be studied. Even with all these studies and strategies, the best we can do is to prolong the lives of the AIDS patients who may be sexually active and thus may spread the virus to others. Antiretroviral research is not done in boardrooms and committee meetings.

It is time for those who claim to be experts in this field, to roll up their sleeves and get to work in the laboratories and clinics to prove their mettle. Antiretroviral therapy is not a tea or beer party. In the light of difficulties in producing vaccines and the problems of ARV drug resistance, abstinence, condom use and vaginal microbicides are the tools that will have immediate impact on HIV transmission.

With the above facts in mind the anti-HIV program at Noguchi was designed to discover plant extracts that have potential in treatment and prevention (vaginal microbicides).

Aqueous extracts were prepared and freeze-dried. Cytopathicity reduction was used to measure activities against HSV. The modified tetrazolium-based colorimetric assay was used to measure activities against HIV. Ocimum gratissimum, Clausena anisata, Alchornea cordifolia, Ficus polita, and GHX-36 (Latin binomial name withheld for proprietary reasons) inhibited HSV and HIV cytopathicity.

Elaeophorbia drupifera was effective against HIV but not HSV. It was demonstrated that the anti-HIV plant extracts unlike AZT, had significant effects against HIV even after the virus had been integrated into host cell genome. Thus the plant extracts were effective against late stages of HIV replication. The effectiveness of the plants were more pronounced when treatment was started early after infection. This clearly indicated that early viral events may be targets for inhibition by the plant extracts making them candidates for prevention.

This observation is borne out by the fact that four of the plant extracts tested against HIV reverse transcriptase showed concentration-dependent inhibition of this enzyme. Further studies on this enzyme by polymerase chain reaction assays indicated that in addition to inhibition of proviral DNA synthesis, proviral DNA copying is also inhibited by these plant extracts.

As has been explained earlier on, HIV infected patients harbour chronically infected cells that serve as unstoppable factories of virus production. It was hypothesized that in order to be able to effectively treat AIDS patients, these chronically infected cells would have to be destroyed. After several months of hard work, HIV-1 chronically infected cell lines and HIV-2 chronically infected cell lines were cloned in the Virology Unit of the Noguchi Memorial Institute for Medical Research.

The aqueous extract of Elaeophorbia drupifera was found to selectively kill HIV chronically infected cells at concentrations that do not affect normal cells. There is no other existing drug that is capable of eliciting this novel activity. Fusion of uninfected cells with chronically infected cells occurs independent of events in acute infection.

The fusion of uninfected cells with chronically infected cells occurs within 12 hours of co-culture. It involves an interaction of gp120 of infected cells with CD4 receptors on the uninfected cells. The fact that the plant extracts, unlike AZT, inhibited this kind of interaction, indicates that they may be useful in the prevention of cell-associated virus transmission. In fact, this proved to be so as the three leading plant extracts (Ocimum gratissimum, Alchornea chordifolia and GHX-36) effectively prevented CD4-dependent and CD4-independent transmission of HIV-1 in vitro. The mechanism of prevention of HIV transmission was found out to be inhibition of HIV attachment to host cells. These three plants are therefore potential vaginal microbicides for the prevention of HIV infections provided they would meet certain pharmacodynamic, pharmacokinetic and toxicologic parameters.

Pharmacodynamically, potential vaginal microbicides should be able to completely prevent transmission of HIV and other sexually transmitted viruses. Pharmacokinetically, the microbicidal activities should not be affected by the acidic condition and mucus in the vagina and there should be minimum absorption of active compounds into systemic circulation. Toxicologically, the microbicides should not have adverse effects on beneficial lactobacillus in the vagina, should not be irritating to vaginal epithelium, should not be teratogenic, should not be mutagenic, and should not be spermicidal.

The three plant extracts effectively prevented HIV and HSV transmission in vitro, were not affected by acidic conditions or presence of mucus and did not affect beneficial lactobacillus flora. HSV genital transmission was also effectively prevented in 67% of female mice by unformulated Ficus polita and GHX-36. It is hypothesized that formulated plant extracts would achieve 100% protection against genital HSV-2 transmission in female mice. Effects on the other parameters are yet to be tested.

It may look as if too much work and money would be involved in following stringent preclinical studies for the development of anti-HIV/AIDS plants. We must however remember that only societies that invest in science will reap the benefits of science. It has been twenty one years since Dr. Barbara McClintock was awarded the Nobel Prize for her life-long research on corn genes that resulted in the jumping gene theory. Since then, the developed world has taken advantage of molecular biology to make many discoveries to advance medical knowledge and applications.

Pertinent to this lecture is the development of Plantibodies Technology. Today, this technology enables the production of unlimited quantities of pharmaceutical-grade antibodies and related molecules at prices significantly lower than animal cell culture-based systems, while also reducing manufacturing capital by 90%. Epicyte Pharmaceuticals Inc. has used this technology to produce HIV-1 anti-gp41 and anti-gp120 immunoglobulins A (IgA) in corn plants. These secretory antibodies are expressed in the seeds of corn. The company intends to use formulations of these antibodies as vaginal microbicides against HIV transmission. It is just a matter of time before scientists in the advanced world would use the same technology to produce medicinal plant products using simple plants like corn. When that happens, our medicinal plants will no longer be needed by them. We can of course take advantage of having such medicinal plants on our continent and muster the political will to take the lead in medicinal plant research.

Let us remember the biblical story where the master gave talents to his subjects and traveled. On his return, he found out that one of his subjects had not utilized his share of talents to produce anything. He took the talent from this subject and gave it to those who had made use of their talents. Africa is the most natural resources-endowed continent in the world. If we refuse to develop what the master of this world has given to us, he will take them from us and give them to those who can develop them.

I started this lecture by emphasizing how important zoonotic diseases have become in this twenty-first century. The manner in which South East Asian countries handled the outbreaks of SARS and bird flu should be a lesson to Ghana. The question is : are we prepared?

Early this year, it was reported that the bird flu virus that made poultry sick had jumped to humans in a number of Asian countries. The incubation period in humans was a mere 3 days on infection with the H5N1 strain of bird flu virus and mortality was high (8 out of 10 patients in the first instance in Vietnam). Within a month at least 50 million Asian chickens were slaughtered and all poultry exports were banned by governments in affected countries. This immediately contained the outbreak. Should the bird flu strain infect a person with a human flu strain, the two viruses could produce a hybrid combining the deadliness of bird flu and the contagiousness of human flu which may well usher in a new pandemic disease. The timely intervention by South East Asian governments with almost total reliance on their own scientists may well have prevented an outbreak of pandemic proportions.

A similar case can be made for SARS. Should viruses that spread by aerosol jump from animals to humans in Ghana would we have the resources to halt their rapid spread? My answer is no.

It would interest most of you to know that the outbreak of monkey pox in humans in the US in May 2003 was traced to Gambian Rats imported from Ghana to the US. The virus was transmitted into humans after passing through another host, the Prairie dog.

Ghana should therefore begin to set up a rapid response team for outbreaks of infectious diseases. This team should be made up of on-the-bench scientists and clinicians and not administrators. Protocols on the containment, isolation and identification of viruses and bacteria should be written and emergency situations simulated occasionally to keep personnel always prepared.

HIV/AIDS infection is one disease condition that the world knows how to contain because of its mode of infection. It is also a viral infection that established itself in humans long before it was detected. It can therefore not be eradicated by elimination of the original host from whom it was transmitted to man.

As indicated before, prevention is the more likely method for containment of this disease. Vaginal microbicides have taken the lead in this regard. However, the haste with which vaginal microbicides are being developed is alarming, with many companies jumping to clinical trials without proper and careful preclinical studies.

With the growing strength of animal rights activists, multinational drug companies have turned to sub-sahara Africa as a large laboratory animal facility. Vaginal microbicides such as SAVVY (C31G) and Carrageenan are being tried in sub-sahara Africa without any convincing preclinical scientific basis whatsoever. It is our women, the very people we are supposed to defend, who are put at tremendous risk in these irresponsible clinical trials.

SAVVY was tested for virus prevention in animals at a concentration of the drug that causes severe vaginal irritation and yet had only mild preventive action. Carrageenan was made to look like a very good drug for the prevention of virus infection by misinterpretation of data. A careful analysis of the data shows that in fact this drug produces only very mild protection against herpes simplex virus infection in animal models.

Carrageenan degraded products have also been shown to be highly toxic. One of the conditions for carrageenan breakdown is acidic environment which is present in the vagina of sexually active adults. I do not dispute the fact that a drug may not be very effective in animal models but may show good efficacy in humans. Moreover, the toxicology of a drug in animals may not be the same as in humans. I however maintain that the animal models for drug development have been very carefully chosen to simulate the human condition. We must therefore not open the door wide for drugs with no proper preclinical data to pass through. If we do otherwise, we would leave ourselves open for a future drug-related disaster of a magnitude greater than the thalidomide disaster.

The history of drug therapy development is punctuated with serious side effects that have led to the withdrawal of many drugs. They may result from unforeseen circumstances or inadequate toxicity tests prior to the clinical use of the drug. As a country which is largely an end user of drugs developed elsewhere, it is absolutely necessary that we develop the minimum capacity to evaluate the data on safety of drugs before allowing their use in the country. This capacity is presently not functional.

Evaluation of safety of drugs is no easy task even in developed countries. When drugs being developed have potential benefits to developed countries it is reasonable to expect these countries which stand to benefit to also bear some of the risk in the clinical evaluation of the safety of the drugs. Yet increasingly developing countries are bearing most or all the risks in human clinical trials. There are several reasons for the predicament we find ourselves in.

The devastating effects of some of the diseases in developing countries weaken our resolve in so many ways to question critically the safety in human trials before they are launched. Our resolve is further undermined by negative publicity in the international media when we question efficacies and safety of drugs or vaccines as we have seen in relation to the Polio vaccine in Northern Nigeria and AIDS drugs in post apartheid South Africa.

In developed countries, effective monitoring of drug safety ensures that drugs that turn out be harmful during clinical usage are promptly withdrawn and victims of unintended side effects are often adequately compensated. In developing countries however, drug monitoring is poor and when harm is caused, a less robust legal system and limited financial resources of victims stand in the way of successful prosecution of international drug companies or their local agents. Another problem to contend with is the woefully inadequate vigilance on the part of our governments in the conduct of human clinical trials.

Finally, where more pressing matters engage the attention of Governments, expenditure on research and development always suffer. This weakens rapid response capabilities and alertness in assessing drug safety before introduction. It also hampers effective quality control programs that are necessary to ensure that newly introduced drugs retain their highest levels of efficacy and purity..

Let me use two typical examples to illustrate my point.

In 1996 there was an outbreak of cerebrospinal meningitis in Kano, Nigeria. With the rapid rise in the death toll, the state radio asked families to rush their sick children to the Infectious Diseases Hospital where the aid organization Medecins Sans Frontieres (MSF) was providing free emergency treatment. Unknown to the parents the giant American drugs company Pfizer was also at the hospital, conducting tests on a powerful new antibiotic drug known as Trovan. The children who received Trovan later developed severe neurological disturbances resulting in death, deafness, blindness etc. There is now a debate as to whether Pfizer got true consent from the parents and whether Pfizer received prior approval for the test to go ahead from the relevant authorities in Kano. Incidentally, the drug has been withdrawn from European and American markets following severe liver problems and death in some Trovan patients. It is this experience that explains the apprehension and mistrust the people of Northern Nigeria have towards the polio vaccination program.

Until recently, the leading vaginal microbicide was nonoxynol-9. It is now widely accepted that nonoxynol-9 enhances rather than prevents vaginal transmission of HIV. Surprisingly, it was only on January, 2004 that Durex Consumer Products announced that as of March 31, 2004, it would become the first of the three largest condom manufacturers to stop offering nanoxynol-9 lubricated condoms for sale and distribution. Unfortunately, the other two large condom manufacturers, Ansell Ltd., maker of Lifestyles condoms and Church & Dwight Company, maker of Trojan, are still refusing to discontinue production of their nanoxynol-9 condoms. Should some of these nonoxynol-9 lubricated condoms appear on the market in Ghana, this would be disastrous for the fight against HIV transmission in the country.

Mr. Vice-Chancellor, distinguished guests, this inaugural lecture has demonstrated my commitment to my long-term objective to research into treatment and prevention of sexually transmitted viral infections.

My major contributions in the field of Antiviral Chemotherapy are:

1. Investigations Into Appropriate Combination Chemotherapy Against HSV Infections;

2. Elucidation Of The Molecular Basis For The Differential Activities Of Nucleoside Analogs Against Wildtype and Drug Resistant Strains Of HSV-1 and HSV-2;

3. Pharmacokinetic Basis For Decreased In Vivo Efficacy Of Anti-HSV Nucleoside Analogs;

4. Development Of Novel Methods For Detecting Anti-HIV Drugs;

5. Investigations Into The Pathology And Susceptibility of Some Ghanaian HIV Isolates To ddCyd And ddIno;

6. Discovery Of Medicinal Plants With Anti-HSV And Anti-HIV Activities.

My contributions in other areas of virology and medicine are:

1. Studies On Pathology And Opportunistic Infections In Aids Patients;

2. Studies On The Changing Trend Of HIV Type Prevalence In Ghana By Virology And Molecular Biology;

3. Isolation And Partial Identification Of The Virus That Is Suspected To Cause Chronic Fatigue Syndrome;

4. Adaptation Of The Modified Tetrazolium-Based Colorimetry For The Detection Of Antimalarial Activities.

I have tried as much as possible to leave out details of my work in order to reach out to all sections of the audience and I hope that I have succeeded in doing so. The detailed methods and data will be presented in a series of lectures planned for the future at which time, questions can be asked and ideas shared.

The anti-HIV plant extracts discovered at NMIMR have great potentials as vaginal microbicides and yet further development for their use has been stalled. With very little financial support, I have had to spend nearly $7,000 of my own money on patent applications which had to be abandoned because of lack of funds. The billions of dollars being spent around the world are targeted for social services, advocacy, and clinical trials. Even though USAID supported the work that led to the discovery of the anti-HIV plants, the same organization has refused to fund further research that will pave the way for clinical trials to begin. I therefore have no choice but to state that this inaugural lecture puts closure on my work in Anti-Viral Chemotherapy at NMIMR until funding becomes available.

(Yen ara yen asase ni, eye aboodeden ma yen. Mogya na yen nananom whie gui de too ho maa yen. Adu me ne wo so. Se ye beye bi de atoa so. Oman yi se ebeye ye o, oman yi se erenye ye o, omanfo bra na ekyere) - written in Akan language.

I would like to first of all thank the Almighty God who has given a purpose to my life. My appreciation goes to my extended family of Pone, Mamfe-Akuapem, that nurtured me to be kind, hardworking and faithful to the truth. Particularly, I appreciate the love and care of my late grandparents (Elias Michael Ayisi and Eugenia Denne Ayisi) and my late parents (Mark Dabiete Ayisi and Elizabeth Adobea Ayisi).

To my wife and children, thank you for tolerating my long hours of work and standing by me throughout the difficult days at NMIMR.

My special thanks go to the CPP government of the first republic for creating the political and economic conditions that helped me to go through secondary school and university at the expense of the people of Ghana. I do hope that I have been able to justify the investment made in me by the people of this country. To fulfill the purpose of God, many people have helped me in several ways.

Thank you very much Hon. Mr. F. K. Buah for instilling discipline in all students who passed through Tema Secondary School when you were the headmaster. Thank you Dean T. S. Williams (of blessed memory) for admitting me into the School of Veterinary Medicine, Tuskegee University, at a time I did not have a first degree.

My special thanks to Prof. V. S. Gupta (university of Saskatchewan) for his guidance in the field of Antiviral Chemotherapy. Prof. Stephen Sacks of University of British Columbia (of blessed memory), you were an inspiration to me, my mentor in infectious diseases and a friend in deed and I cannot thank you enough for what you have done for me. Seth Yao Ntiamoah Gbetanu (of blessed memory), thank you for your numerous letters that made me feel at home even though I was thousands of miles away. I wished you were here today to share this moment with me. Mrs. Alice Lamptey, thank you for making it easy for me to settle down to work at NMIMR. Mrs. Regina Appiah-Opong, thank you for your wise counsel throughout the years we have known each other.

To my two former Research Assistants (Michael Aidoo and Caesar Nyadedzor) and my former Technician (Albert Magnusen) I say thank you for your dedication to work and staying on my research projects despite the difficulties we encountered at that time. I thank God that Michael completed his PhD at Oxford some years ago and is now employed at CDC in Atlanta, Caesar is doing his Masters in England and Albert is doing his PhD in the USA.

My collaborators and consultants have been numerous and I would like to thank those I have already not mentioned: Erik De Clercq, MD,PhD, Rega Institute for Medical Research, Belgium; Lawrence Stanberry, MD,PhD, Department of Pediatrics, Univ. of Texas Medical Branch, USA; David Bernstein, MD,PhD, Department of Infectious Diseases, University of Cincinnati, USA; Russel Mumper, PhD, College of Pharmacy, Univ. of Kentucky, USA; Margaret Mensah, MB,ChB, Ministry of Health, Ghana; Masanori Hayami, DVM,PhD, Kyoto University, Japan; M. Ito, MD,PhD, Yamanashi Medical University, Japan; Koh-Ichi Ishikawa, DVM,PhD and Testutarou Sata, MD,PhD, National Institute of Infectious Diseases, Japan; Vince Tsiagbe, PhD, New York University Medical Center, USA; K. Taneguchi, MD, Mie National Hospital, Japan; M. Newman, MB,ChB,MPH, Achimota Hospital, Ghana; E. K. Wiredu, MB,ChB,MRCPath,MIAC, Department of Pathology, UGMS; C. N. Cofie, MB,ChB, Department of Medicine and Therapeutics, UGMS; Mr. D. K. Abbiw, Botany Department, Univ. of Ghana; Mr. Alex Ayim, Electron Microscopy Unit, NMIMR.

This inaugural lecture has been made possible by friends who made very valuable suggestions: George Kweifio-Okai, PhD, Biomedical Research Scientist, Australia; Nanabanyin Ghartey-Tagoe, DVM,PhD, Department of Pathology, Tuskegee University, USA; Abenaa Ghartey-Tagoe, BSc,MSc,MBA, Dpra Consultants Inc., USA.; Michael Aidoo, PhD, CDC, USA.

Let me take this opportunity to recognize the presence of two very important personalities - 1. Nana Ansah Sasraku III, Mamfehene and Kyidomhene of Akuapem; 2. Nana Obeng Kumi II, Mamfe Mankrado.

I thank all of you for having the patience to come and listen to me this evening.

Finally, I would like to state that if my work in Antiviral Chemotherapy could stimulate some Ghanaians to make careers in this field, then my struggles in medical research at NMIMR would not have been in vain. I dedicate this inaugural lecture to the memory of Afua Anima Ayisi, my little sister who died before reaching the age of two years. Again thank you for coming and have a great evening.