COIU/J. Biochrvri. Physiol. Vol. 75A. No. I, pp. I I7 to 121, 1983 Printed in Great Britain

BOOK REVIEWS

Special programme for research and training in trop- ical diseases-Fifth annual report of UNDP/World Bank:WHO. WHO, Geneva, Switzerland

This volume of 280 pages describes the progress and developments over the year July 1980-July 1981.

Work has continued on the development of meflo- quine with clinical trials in Brazil, Thailand and Zam- bia. In association with Chinese scientists, progress has been made with the pre-clinical development of Qing Hao-su (artemisine) and its derivatives, some of which have shown significantly higher activity than the parent compound. Work has continued on the development of kits for performing the micro-test for the sensitivity of malaria parasites to drugs. Such ex- perimental kits are currently being evaluated in ende- mic countries.

The development of tissue schizonticidal drugs was reviewed and work continued on the metabolic path- ways in malaria parasites, with some comparisons among strains which differ in their response to drugs.

The immunology programme has received a major stimulus through the introduction of the cell-fusion (hybridoma) technique for the production of monoc- lonal antibodies. Several institutes, both inside and outside the programme have taken up this line of research. with particular emphasis on parasite-inacti- vating or growth-inhibiting antibodies, especially those interacting with surface antigens of sporozoites, merozoites and gametes. A protective monoclonal antibody directed against a sporozoite surface antigen of P. herglwi has been produced and used for the isolation of the relevant antigen which is undergoing further analysis, with a view to eventually reproduc- ing and mass producing the antigen through modern methods of genetic engineering. At the same time, the system is being applied to P.fticiparum. As a result of the recent advances in hybridoma and recombinant DNA techniques, the concept of vaccine development has shifted from the use of crude whole-parasite to that of defined protective antigens. Besides investiga- tion on the mechanisms of immunity; immune eva- sion. immunosuppression and immunopathological phenomena. and the further development of immuno- diagnostic tests is supported. A solid-phase radio- immunoassay for the detection of low numbers of malaria parasites in blood has been adapted from a rodent model to P. fdciparurn. It detects parasites down to a level of 8 parasites per lo6 RBC.

Progress has been made in the irl vitro cultivation of blood stages of P. ,fdciparum and other plasmodia uhich should eventually lead to the culture of P. rmrhrirre and P. GUU.Y. The in vitro cultivation of exoerythrocytic stages of P. herghei from sporozoites to infective merozoites, will facilitate the development of irl vitro screening systems for tissue schizontocidal

compounds and, for the first time, render feasible studies on sporozoite invasion. The production of viable gametocytes (P. jidcipuruw) from in rifro cul-

ture has opened a way to raising sporozoites in the number needed for chemotherapeutic and immuno- logical research. Besides these studies particular emphasis was given to membrane studies--of both erythrocytes and parasites-to elucidate structure and function in relation to invasion. material and energy transport, and antigenic components.

High priority has been given to global studies on the drug resistance of malaria parasites, especially P. fulciparum. Besides the assessment of baseline and the monitoring of drug sensitivity levels, major efforts are directed at the development and strengthening of methods for the containment of drug resistant malaria. These activities have been consolidated in the coun- tries of the South East Asia and Western Pacific Regions and some progress has been made in imple- menting them in other regions. Further essential research activities are focussed on studies of the oper- ational use of antimalarial drugs and community par- ticipation in antimalarial measures, vector control in areas with exophilic or insecticide-resistant anophe- lines. and epidemiological research as the base for rational planning and evaluation of malaria control. Special efforts are being made in research training and in the improvement of field research capabilities of national antimalarial services and scientific insti- tutions in tropical, malarious countries.

One of the major problems has been the supply of monkeys. Although a funded project with the NuKeId Institute of Comparative Physiology. London, has provided Aotus monkeys on a small scale, it is not feasible to establish breeding centres which could meet the needs of the programme. An exclusive mon- key colony for rhesus monkeys and eventually AO~KY and Suimiri monkeys, including breeding units. is being set up at the Central Drug Research Institute. Lucknow. Facilities will be available in this unit for visiting workers. In addition, breeding programmes for Aotus and Suiruiri monkeys in several institutes are being established. but these are not yet oper- ational.

With regard to applied field research, work has been done on the integrated approaches to the con- trol of schistosomiasis in man-made situations~~large dam lakes and irrigation systems. The use of focal mollusciciding based on ecological requirements is being investigated in the Sudan, as is the study of the dynamics of snail transmission in different irrigation systems. In another study, the impact of chemo- therapy on high density S. r~~cu~sor~i infection is being examined.

Research has proceeded on the intermediate snail hosts of schistosomiasis including studies on ecology.

117

118 Book Reviews

snail behaviour and the role of attractants. the gen- etics of resistance to infection with schistosomes, and the life cycle of the parasite within the snail. Meta- bolic pathways in snails are being explored in the hope of identifying suitable targets for molluscicidal action. A slow release formulation of a molluscicide is undergoing laboratory development and testing.

A collaborative study for immunodiagnosis involv- ing eight laboratories has recently been completed. Research in this field of immunology has been helped by providing parasite material. e.g. lyophilised adult

Some basic biochemical studies have been designed

worms and eggs of S. mmsmi. The immunological

to elucidate the mode of action of schistosomicidal drugs as well as the pharmacological properties of these agents in man. Niridazole and metrifonate have

responses of the mammalian host to bilharzia infec-

been examined in this way. Clinical evaluation of new’ drugs has also been supported with trials on prazi-

tion are being studied, including work on the mechan-

quante, a drug developed by industry in collaboration with the Schistosomiasis Unit of WHO.

ism of resistance to infection.

Fi/uriu.si.s

The aim is to improve the use of existing tilaricides and to find new ones; to find means of reducing the inflammatory reactions that occur in the human host in response to the presence and death of filarial worms. Immunological research is aimed at identify- ing filarial antigens to be used in serodiagnostic tests. and perhaps for the development of vaccines.

During the reporting period, over 3000 compounds have been tested in various screens, Compounds which show activity in the primary screens are sub- jected to further evaluation and the promising ones are put through the cattle screen of infection with Ofzckocerco gihsmi an d 0. gutturosrr. So far three compounds have shown high macrofilaricidal activity in this screen, Flubendazole suppressed embryogenesis in the cattle screen. more markedly in 0. qihsmi than in 0. gurturosu, and was found to be more effective when given by injection than by the oral route. New chemical compounds. synthesized around existing leads, are being screened for anti-filarial activity.

Microfilarial density was markedly reduced (X8”/, reduction) in patients treated with mebendazole in combination with tetramisole. Mebendazole alone or in combination with tetramisole has a chemosterili- sant effect as shown by nodules which were examined after treatment. Studies using radiolabelled diethyl carbamazine have provided new information about the handling of this drug in the human body. The rate of excretion of the drug is apparently influenced by the pH of urine. Most of the drug is excreted as unchanged drug but X:‘,, is excreted in the urine as DEC-,Y-oxide. Work has continued on the identifica- tion and characterization of antigens for serodiag- nosis. Some models have been designed to study the pathogenesis of ocular lesions in onchocerciasis. Some progress has been made with regard to the vectors of both lymphatic tilariasis and onchocerciasis. and some epidemiological studies have been funded. An onchocerciasis mathematical model. which gives pre- dictive stimulations of control strategies. has been de- veloped.

Recent results have promoted the understanding of the epidemiology of this disease. Several game ani-

With regard to drug development, interest has been

mals have been shown to harbour trypanozoon stocks, some of which appear to be identical with

shown in compounds which can disrupt threonine

human stock of Trypurmomu h. gurdkw. This com- plements the earlier finding of similar infection in

metabolism and those which affect the enzyme ornith-

domestic animals-pigs and dogs. Further confirma- tion has been obtained of the earlier finding that tsetse

ine decarboxylase of the parasite. Screening of poten-

flies travel over much longer distances than had been

tial trypanocides continues at two centres, one in

assumed in the past. Another field trial of the ion- exchange mini-columns for parasitological diagnosis was carried out. this time in a T./I. rhodr.sierm ende-

Kenya and the other in the Federal Republic of Ger-

mic area. The direct card agglutination test for trypa- nosomiasis (CATT) has been further improved to

many. Pharmacological studies continue on the drugs

achieve better fixation of the antigen to the card.

in current use +mtrypol and organic arsenic&. Although immune complexes are found in the sera

of patients with and without cerebral complications in the cerebrospinal fluid. complexes were found only in the meningoencephalitic stage. Work continues on the antigenic variation in these parasites. with regard to the repertoire and also the mechanism for its occur- rence.

An important objective is to improve knowledge of the geographical distribution, prevalence and clinical varieties of Chagas’ disease and of the distribution of its vectors. Field research on the prevalence and dis- tribution of the disease has been initiated in several endemic countries. Studies using standard protocols and methods have been initiated in three countries, Some results have been obtained on the analysis of blood meals as a means of assessing the relative role of potential vectors in different geographical areas. A field evaluation of a slow release polyvinylchloride- based paint showed promising results with effective control of the insect vector for nine months. Work has continued on the study of the mode of action of organophosphorous compounds on Triurowu i+s-

turn.. Work on the metabolic pathways of Trypuw-

smzu crxi continues to yield interesting results in- cluding studies on the salvage and interconversion of purines. de tmo biosynthesis of pyrimidine and analy- sis of the respiratory chain. Several potential trypano- tides have been identified, and more compounds are being screened.

A comparative serological study was initiated in July 19X0 and three laboratories are currently colla- borating in the project. In a project based in Brazil. reference sera from patients and uninfected controls have been collected and are being made available to scientists for standardization of their tests. Mechan- isms of the pathogenesis of Chagas’ lesions are being elucidated with particular interest in the role of antt- bodies against endocardium. vascular structures and the interstitium of heart and striated muscles. as well as those antibodies active against peripheral nerves.

Book Reviews 119

Focal lesions resulting from intracellular parasitism of muscle cells have also been reported.

Work on antigenic analysis is making good pro- gress; specific antigenic components are being ident- ilied by the use of monoclonal antibodies.

Epidemiological surveys are currently in progress in I7 countries and the preliminary data obtained will be examined and analysed later this year. The animal reservoirs of both the cutaneous and mucocutaneous visceral forms are being identified in different geo- graphical locations.

Type collections of sandflies from many different parts of the world are being catalogued at the British Museum for taxonomic purposes and for the training of scientists. Blood meal identification is being widely used to incriminate local vectors.

Efforts continue to be made to obtain more exact typing of leishmanial strains. In addition to the use of standard serological, biochemical (enzymological and biological characteristics. a new technique using radio-respirometry has provided informative results. Although the latter method is too complex for routine use. it could prove valuable for definitive classification of reference material.

Clinical evaluation of promising drugs has con- tinued. It was again confirmed that nifurtimox shows some effect in cases of mucocutaneous leishmaniasis, but on its own the drug did not achieve a high cure rate. In combination, it improved the results obtained by treating with meglumide antimoniate alone. Allo- purinol. which had shown irr ritro activity, has so far proven disappointing in clinical trials in cases of visceral leishmaniasis. The observation in experimen- tal animals that entrapment in liposomes enhanced the therapeutic activity of some antileishmanial drugs, was initially made by scientists vvorking outside the programme, and this approach is now’ receiving sup- port in the hope of applying this technology in human disease. A modest screening effort is continuing and interesting activity has been identified with a few compounds. Meanwhile, biological screens for cuta- neous and visceral disease are being developed and evaluated. In a series of experiments on the problem of treatment failures. the strains of L. doriouarii involved exhibited resistance to the drug meglumide antimoniate. At a workshop on the chemotherapy of mucocutaneous leishmaniases, agreement was reached on standardized protocols for drug trials including the selection of patients, identification of the parasites. treatment schedules, follow-up and criteria of cure.

The immunology section has supported work on diagnosis using modern techniques of antigenic analy- sis and specific monoclonal antibodies. Mechanisms of immunity are also being studied. With the demon- stration of cross-reacting antigens between L. rwiettii

and L. tropical. the possibility of using the former non- pathogenic species as a vaccine is being explored.

Work on the development of the anti-leprosy vac- cine continues to make good progress. Experiments in mice confirm the protective effect of four different preparations of killed Myohtrcteriur~~ Irprue. The pre- ferred procedure (protocol l/79) produces a high

yield, with minimal damage to bacteria and minimal contamination. It is proposed to undertake the testing of the immunogenic potential of this preparation with and without BCG in human beings as the first step in the vaccine trials.

Immunodiagnostic tests are being further devel- oped. An ELISA test of comparable sensitivity to the radio-immunoassay test to M. leprae has been estab- lished. A method has also been developed for early detection of systemic infection in armadillos, and monoclonal antibodies are being evaluated for their specificity for M. leprae.

Clinical trials of drug combination continue. At one centre, several cases of jaundice led to the suspension of one regime but investigations suggest that drug toxicity was not cause of the jaundice. Detailed proto- cols for field trials of chemotherapy of lepromatous leprosy were drafted and two trials are expected to start soon. With regard to drug development, ana- logues of thalidomide and of rifampicin failed to yield promising leads, but work continues on analogues of ethionamide and rations of dapsone. Surveys are being carried out on the frequency of primary dap- sone resistance in endemic countries. One report from The Philippines showed a prevalence of 2.1% of new cases of lepromatous leprosy. Results from other geo- graphical areas are expected soon.

Ongoing projects include the use of recombinant DNA technology for the study of kinetoplast DNA in Trypmosorw lewisi and of the variant antigen sequences of Tr~~puriosomutids. Work is progressing on the gene organization and function of parasitic protozoa. The role of factors under genetic control in relation to susceptibility to infection is being investi- gated with regard to G-6-PD deficiency and P. ftilci- purtm infection in man. Two studies in animal models are investigating genetic factors in relation to leishma- nial infections. Studies are being carried out on the role of cell surfaces and recognition phenomena. The metabolic pathways of parasites are being investi- gated, including purine metabolism in trypanosomes, the role of oxygen reduction products in the killing of parasites and the sensitivity of variant forms of super- oxide dismutase to cyanide.

Bio/o~gica/ coiltrol of‘ vectors

Of the microbial agents, the highest priority has been assigned to BaciUus thuringiensis, serotype H-14, which has now reached the stage of large scale testing for the control of mosquito and blackfly larvae.

Tests have shown that it is a potent non-residual larvicide of mosquito and blackfly larvae, with a large safety margin for man and other non-target organ- isms, The activity of the agent is not affected by sali- nity, pH within reasonable limits and water tempera- ture, but is less effective in polluted than in clear water. The delta endotoxin is stable under tropical conditions.

Work continues with another bacterial agent, B.

sphuericus. Safety tests show that this agent is inno- cuous for mammals under normal conditions of ex- posure and environmental studies show no harmful effects on non-target organisms. The agent is patho- genic for larvae of C&Y and certain species of Ano-

I20 Book Reweus

~&/es, but much less effective against A&s. For the further development of the agent, improved formula- tions and reliable standardization methods are required.

Cu/icirlo~l~~~s &IU~.S~X~~U.S, a fungal agent. is also being studied as a potential biological agent for the control of mosquito and certain other insect larvae.

Of the non-microbial agents, a high priority has assigned to the fish Gtrrnh~sicc @j~i.s. The use of this and other larvivorous fishes will be reviewed at a special consultation later this year. A variety of other agents are being systematically examined according to the standard scheme for investigating potential bio- logical agents.

The Social and Economic Research Group has

Cocused on the major objective of increasing the effec- tiveness of disease control programme through the integration of human behavioural factors in pro- gramme design and management. In this context. be- haviour was defined to include social, cultural and economic factors. Most of the projects funded so fLr relate to the intermediate objective of defining the relationship between these factors and the trans- mission of diseases and their control. As far as poss- ible. the projects are being developed in association \rith ongoing epidemiological research or control pro- grammes.

Early results from funded projects include ;I pre- liminary report on knowledge. attitudes and behav- iour with regard to malaria. In this study. the scicn- tists sought the reasons for declining collaboration of the population with indoor spraying of DDT in the control programme in Thailand. In another study. the role of the school in the control of locally endemic diseases was examined through a questionnaire ad- ministered to primary school children in Nigeria. Human vector contact in relation to African sleeping sickness is being studied in an endemic area of Upper Volta.

The objective of the Research Capability Strength- ening Area of the Special Programme is to assist de- veloping countries where the six diseases are endemic to assume their appropriate role in the research required to identify, analyse and solve the health problems caused by these diseases. The goals and ac- tivities of this Programme Area arc interdependent with those of the Research and Development Area although there arc important differences in the nature of the projects which are supported.

The scope of activities has increased rapidly during the reporting period and 22 institutions are now receiving support on a long-term basis while another 26 habe received short-term and capital grants. In ad- dition. other institutions are being supported on a long-term basis to enable them to conduct formal courses at ;I Masters degree level. The support of training activities also has expanded: over 210 scien- tists have received individual research training grants and approximately 40 short-term group learning ac- tivities have been supported in endemic countries. Over 100 trainees have now returned to their home institutions in developing countries. and about a

quarter of that number are being supported by re- entry grants to enable them to apply their knowledge and skills in local situations.

The strategic plan for this area of the Programme. which was formulated and implemented in 1979 for 19x0, will be reviewed in the light of both progress during the past two years and the findings of the Scientific and Technical Review Committee which is in the process of carrying out an in-depth review of the Programme Area. The development of a durable network of institutions in endemic countries. which is an objective of this plan. involves a strategy of shifting resources to less developed institutions, while those which initially received support assume responsibility for their own research and training activities. This has been illustrated bq the Ndola Tropical Diseases Research Centrc which initially started as a WHO activity. Houcvcr. as of the 1st of January 19x1. the Government of Zambia assumed responsibility for the management of the Centre. and a Zambian physician scientist was appointed as its first director. The Centre continues to collaborate with the Special Pro- gramme for research m epidemiology and clinical pharmacology; it is also playing an important role in the training of scientists from other developing coun- tries.

This is but one of a number of examples of the policy of promoting technical co-operation has occurred through training activities which can lead to the forging of links amongst developing country insti- tutions. Of the 53 scientists supported by Research Training Grants and Visiting Scientist Grants between I July IWO and 30 June 19X 1. 21 will have undcrtakcn all or most of their training in developing countries other than their own. The host countries are: Brazil. Ethiopia. Ivory Coast. Kenya, Thailand, Malaysia. Singapore. Venezuela and Zambia.

Interaction between scientists from developing countries also occurs through the short-term work- shops:scminars and long-term courses. All these group Iearning activities were located in developing countries and were planned and implemented by local scientists; all included participants from other devel- oping countries. Seven of the institutions receiving long-term support are activcl? engaged in group training activities involving nationals from other de- veloping countries.

Activities in the Research Capability Strengthening area have been expanded to provide for collaboration between supported institutions so as to achieve ;I nctv,ork on research and research training institutions in countries where the diseases are endemic. This wider perspective has spauned several additional stra- tcgics now being implemented. Among these are:

---training workshops in research management for those scientists playing a managerial role in insti- tutional development programmes. The first 01 such workshops was held on a global level and plans have been made to hold others at a re- gional level : meetings for scientists working in developing countries for the purpose of exchanging infor- mation which has not yet been formally pub- lished and for exchanging experiences in insti- tutional development:

Book Reviews 121

-further promotion of training and the develop- The Enchanted Ring. The Untold Story of Penicil- ment of training programmes in endemic coun- lin-by JOHN C. SHEEHAN. 242 pp. 1982. MIT Press. tries: $15.

-promotion of the development of research man- power in institutions on the basis of nationally approved. explicit longterm plans for the devel- opment of the institution.

By mid-July 198 1, 24 governments (including those of 7 developing countries) and 6 other organizations, together with UNDP. the World Bank and WHO, had contributed over US$SO million to the Pro- gramme. The Joint Coordinating Board (JCB), the Programme’s top management body, approved a maximum budget of USS30.09 million for 1981. This amount would permit the Programme to maintain its momentum. However, since it appeared unlikely that funds available in 1981 would reach this level, the JCB approved a contingency plan of financial manage- ment, By mid-1981, the estimates of available funds for the year were still below US827 million and there- fore the budget for 1981 was revised downward to USS26.579 million; in addition, the Proposed Pro- gramme Budget for the 1982-1983 biennium was reduced to USS61.643 million, a decrease of 7% from the 1980 estimates for the biennium.

John Sheehan’s group was the first to synthesise the central ring of penicillin, the beta lactam ring, and produce six amino penicillanic acid (6APA). He was also the first to appreciate the advantage of possible synthesis of new and more specific penicillins. This volume is an account of the discovery of penicillin and the interactions of the various research groups throughout the world. Interesting points come out from the story; for example it appears that when Florey applied to the MRC in September 1939 for a grant of flO0 towards his work on penicillin he was given to understand that he would receive no more than &25!! The policy makers did not consider that research on penicillin was a viable proposition. Toxi- cological testing was intially carried out on rabbits and mice, and showed that penicillin was non-toxic. Had the tests been carried out on guinea-pigs, the story would have been different, for penicillin is toxic to guinea pigs. When it was clinically tested, the first patient showed a reaction to the drug, the second patient also died (due to insufficiency of available penicillin).

During its first five years of operation, the Pro- gramme has received remarkable support from scien- tists throughout the world and has created unprecen- dented expectations in the developing countries. If the scientific opportunities now before us are to be exploited and the hopes of one-third of the world’s population are to be realized, the Programme will require substantial financial support.

The first chemical analysis of purified penicillin failed to detect the presence of sulphur. Argument ensued between Sir Robert Robinson who was con-

vinced that penicillin had the structure of an OX~ZO- lone thiazolidine, and Sheehan who thought it was a beta lactam. Light is thrown on the interactions of Florey. Chain, Robinson, the Beecham Group, Merck, Bristol Myers and many others. The trial and tribulations of patenting a discovery are also indi- cated. It makes very interesting reading.