COLLABORATIVE RESEARCH ON TROPICAL DISEASES (1985)   p.11 of 12

V. Appendix A: SIGNIFICANT ACCOMPLISHMENTS OF USAMRUs

USAMRU – BRASILIA (Source: “Winter Report”)

·            The only laboratory established in the world that currently screens anti-schistosomal drugs for primary prophylactic and curative activity against the Brazilian strain of schistosomiasis.

·            Established the secondary curative test as a means of further evaluating anti-schistosomal chemotherapeutic activity.

·            Identified twenty new anti-schistosomal drugs, four classes of compounds having prophylactic activity, and eight classes of compounds having curative activity.

·            Established the IFAT malaria serological testing capability as a routine procedure at the University of Brasilia.

·            Successful in vitro continuous cultivation of P. falciparum in Brazil (Malaysian strain).

·            Established the in vitro chloroquine susceptibility testing of P. falciparum at the University of Brasilia.

·            Field isolation, cryopreservation and subsequent in vitro continuous cultivation of a Brazilian strain of P. falciparum.

·            Developed a field study area on the Ituxi River, Amazonas, Brazil for conducting clinical, epidemiological, immunological and entomological studies.

·            Established a new field laboratory at Foresta, Ituxi River, Amazonas to document exophilic and endophagic behavior patterns for A. darlingi populations, the major malaria transmission vector in the Amazon Basin.

·            Initiated baseline studies on the ecology and population dynamics of malaria vector (A. darlingi).

·            Initiated steps to establish an Entomological Museum at the University of Brasilia on potential anophelene malaria vectors in Brazil.

USAMRU-KENYA

·            In a short span of time scientists of this unit have shown that T. rhodesiense infections of bovines provide a good model for the pathology of human trypanosome disease.

·            Immunization trials by infection and cure have proven that broad-based protection against an entire serodeme of T. congalense can be induced, and that this protects not only against a trypanomastigote but also against metacyclic (fly-borne) challenge.

·            Study of the antigenic inter-relationships of human trypanosome isolates from the Lambwe Valley demonstrated that as few as one serodeme may exist in an endemic area, and that it is antigenically stable over a long period of time.

·            In leishmaniasis, an in vitro culture system and a leishmania complement fixation test have been established and their utility in the diagnosis of kala azar established.

·            Kala azar in Kenya has been shown to be refractory to current US treatment schedules.

·            Pilot studies of the pharmacokinetics of Pentostam and Glucantime have been undertaken in collaboration with Kenya physicians.

USAMRU-MALAYSIA

·            Demonstrated that with the collection of appropriate specimens and the availability of adequate laboratory tests, a definitive diagnosis can be achieved on over 80% of fevers which had previously been diagnosed as fevers of unknown origin, and that scrub typhus, leptospirosis, arboviral infections and typhoid are the most common cause of fevers; the findings establish the relative importance of these diseases, the appropriate tests and specimens for laboratory diagnosis of fever, and a basis for clinical management of febrile illnesses.

·            Demonstrated that scrub typhus is a common cause of febrile illness in rural Malaysia, accounting for approximately 20% of all fever. Also, scrub typhus infection causes a full spectrum of disease, from mild and asymptomatic to classical scrub typhus; demonstrated that without appropriate serological tests, such as the immuno-fluorescence test, many scrub typhus infections would go undiagnosed. These findings show that scrub typhus is of much greater significance than was previously recognized, and changes the current concept that it usually causes significant symptomatology and frequently requires hospitalization.

·            Demonstrated that the virulence and antigenicity of scrub typhus rickettsiae do not change during either transovarial passage in the vector mites, or in natural passage in mice, monkeys, and man, or in artificial passage in embryonated eggs, nor does the presence of antibody alter this stability. This is the first evidence that shows the organism to be stable antigenically throughout this array of natural and artificial circumstances, an important consideration in progress toward a scrub typhus vaccine.

·            Demonstrated that the preponderance of strains of scrub typhus rickettsiae isolated from patients, rodents and chiggers were antigenically Karp or Karp-like; this finding is important for selection of strain(s) from which to make a vaccine or vaccines.

·            Demonstrated that a single dose of 200 mg of doxycycline was as effective as a seven-day course of tetracycline in treatment of scrub typhus; this finding will lead to a significant alteration in treatment of scrub typhus, with reduced hospitalization and with many scrub typhus patients being treated as outpatients.

·            Demonstrated that young cynomolgus monkeys are a suitable animal model for scrub typhus. This finding is important for vaccine development.

·            Demonstrated that volunteers exposed to the bite of infected mites from laboratory-maintained colonies develop classical disease. This finding will permit an evaluation of doxycycline as a prophylactic, and will also facilitate subsequent vaccine trials.

AFRIMS - BANGKOK

·            In ongoing antimalarial chemotherapy studies, the treatment and transmission of vivax malaria have been studied and hypotheses formulated to explain the resurgence of this parasite in Thailand. The efficacy and safety of the new antimalarial, inefloquine, in treatment and prophylaxis of both vivax and falciparum malaria, has been confirmed. The effect of antimalarials and mefloquine upon the sexual cycle of human malarias, an important consideration in malaria control, has been evaluated. Fansidar resistance in Indochines refugees is being documented. Planned are studies of the efficacy of Halofantrine, a promising new antimalarial drug from the WRAIR antiparasitic drug development program.

·            The cell-mediated immune response to tropical diseases, particularly malaria, is being studied. Findings include the characterization of responding classes of white blood cells, responsiveness of these cells to antigenic and nonantigenic stimulation, and the description of white cell “killer” factors in the sera of malaria patients. These findings are of great importance in understanding the immune response and in vaccine development.

·            Studies to evaluate the efficacy and toxicity of selected experimental antimalarial drugs in rhesus monkeys infected with Plasmodium cynomologj are ongoing. More than 375 compounds have been tested to date. WR 225448, a recently studied compound, has been shown to be six times as active as primaquine as a tissue schizontocide. Two other radical curative compounds with more than 15 times this efficacy of primaquine have been identified.

·            Studies of Anopheles philippinensis, a presumed secondary vector of malaria in Thailand, are ongoing. Results suggest that the current division of this species into two species may not be correct, or that nivipes, the second species, is the common member in Thailand, and that philippinensis is absent or extremely rare. Additionally, it has been clearly demonstrated that what was previously known as A. balabacensis is actually a complex of closely related species. The Thailand form has recently been designated as a new species, A. dirus. This appears to be an extremely important vector of drug-resistant falciparum malaria in many parts of mainland Southeast Asia.

·            Studies in the epidemiology and transmission of viral hepatitis A and B are ongoing. Hepatitis B carriers were found to be common among Thais and to serve as a source of infection. Studies in both urban and rural Thai populations have shown transmission at early ages. Initially, transmission of viral hepatitis occurs within the family, originating largely from carrier mothers, but later it also appeared to result from associations outside of the family. Saliva and semen from chronic carriers of hepatitis B virus were proven to be infectious in transmission experiments using gibbons. Factors relating to transmission of-hepatitis A and B in US troops stationed in Thailand are being studied.

·            The severe manifestations of dengue (dengue hemorrhagic fever and dengue shock syndrome) have been examined in epidemiological and pathogenetic studies. The most recent outbreak of dengue hemorrhagic fever was temporally related to the reintroduction of a virus serotype (Dengue 4) not seen for many years. Information developed suggests that as many as ten percent of Bangkok (Thai) school children may become infected with dengue hemorrhagic fever. This school population may be valuable as dengue vaccines become available for testing. The US Component provided the central laboratory facility to a cooperative WHO study that showed the role of activation of complement in the pathogenesis of dengue shock syndrome.

·            Isolation of dengue virus has been difficult, particularly in patients tested more than three days after onset of illness. Studies have shown wild dengue virus can be isolated from cultures of white blood cells when serum samples are negative. Isolation of dengue virus from white blood cells will allow the precise identification of a large number of previously undiagnosable infections.

·            In 1979, studies have been initiated in Thai children and US Peace Corps volunteers to determine the etiology of diarrhea. These studies also include the relationship between antibiotic resistance and toxin production in entero-pathogenic E. coli and the efficacy of doxycycline in prophylaxis of traveler’s diarrhea in Peace Corps volunteers in Thailand.

·            Studies have started on the epidemiology of combat wound infections in Thai military personnel.

NAMRU-2 MANILA

·            Developed fluid and electrolyte replacement therapy for cholera, reducing case fatality rates from 40% to less than 2%.

·            Showed spontaneous gangrene (blackfoot disease) in southern Taiwan to be due to low-grade arsenic toxicity associated with nutritional deficiency.

·            Penicillamine found to be effective in the treatment of Wilson’s disease by increasing copper excretion.

·            Demonstrated effectiveness of Bithionol in the treatment of paragonomiasis.

·            First described transmission cycle, clinical aspects and treatment of capillariasis.

·            First isolations of Japanese encephalitis virus in Taiwan, Okinawa and the Philippines. Isolated virus from migratory birds, reptiles, swine and other animals. Demonstrated transovarial transmission of Japanese encephalitis virus in mosquitoes.

·            Described epidemiology of scrub typhus in the Pescadore Islands. Developed monocyte culture as improved diagnostic technique. Demonstrated efficacy of weekly doxycycline for prevention.

·            Maintained surveillance for new influenza virus strains. First direct evidence of infection of swine during human influenza outbreak. Described epidemiologic and clinical aspects of first shipboard outbreaks of “Russian Flu;” isolated the virus (A/USSR/77).

·            Showed most frequent causes, excluding malaria, of “fever of unknown origin” in Marine Corps personnel in Viet Nam to be Group B arboviral infections, leptospirosis, and scrub typhus.

·            Discovery and determination of the chemical structure of new hemoglobin variants from Taiwan, Korea, Philippines, Sri Lanka, Viet Nam, Thailand and Bangladesh.

·            Partial mapping of the distribution of arboviruses, schistosomiasis, filariasis, intestinal parasites, and medically important arthropods in the Philippines.

·            Developed first primate model of bancroftian filariasis.

·            Showed Taiwan to have the highest prevalence of hepatitis B surface antigen carriers, and showed the carrier state to be associated with an increased risk of developing hepatoma and chronic liver disease.

·            Developed improved diagnostic tests for schistosomiasis (japonicum), angiostrongyliasis and amebiasis.

NAMRU-2 JAKARTA

·            First definitive description of parasitological, entomological and clinical aspects of Timor filariasis.

·            Determined extent of Schistosoma japonicum and Bancroftian and Malayan filariasis in Indonesia.

·            Documented presence of chloramphenicol-resistant typhoid fever in Jakarta and of chloroquine-resistant falciparum malaria on Sumatra, Flores and New Guinea.

·            Partial mapping of arboviruses and medically-important arthropods in Indonesia; isolation to date of all four dengue virus serotypes and Japanese encephalitis virus; established reference collection of mosquitoes.

·            Rapid diagnosis of typhoid fever through detection of specific antigen in urine.

·            Determined major causes of febrile illness leading to hospitalization in Jakarta.

·            Determined reservoir status of rodents for plague, leptospirosis, scrub typhus and murine typhus.

·            Determined that malaria, arboviral diseases, scrub typhus, diarrhea, and filariasis were the predominant disease risks to population groups relocated from Java to Sumatra and South Celebes.

·            Described spectrum of bacterial agents causing diarrhea in West and Central Java.

Special Efforts:

·            At the request of the Indonesian Government, mounted teams to investigate febrile disease outbreaks in Morotai, Central Java (Bantul), and Lombok.

·            Assisted Indonesian Navy in establishing microbiology laboratory.

·            Microbiological laboratory support and clinical consultation for U.S. Embassy and local medical institutions.

NAMRU-3 CAIRO, 1946-1979

·            Penicillin shown to be effective in treatment of louse-borne relapsing fever.

·            High prevalence of urinary Salmonella carriers in Egypt reported and shown to be associated with urinary schistosomiasis.

·            First medical surveys of Yemen.

·            A new Salmonellas type (S. Cairo) reported.

·            First isolation of Coxiella burneti (Q fever) in Egypt.

·            Demonstration of “spreading factor” in cercariae of Schistosoma mansoni, providing insight into skin penetration and infection mechanisms.

·            MIF technique for identification of intestinal protozoa described, making mass surveys feasible.

·            First report of human intestinal fluke, Heterophyes heterophyes, from the Yemen bat - a possible reservoir for human infection.

·            Sindbis virus first isolated and recognized; now known to be a cause of fever in Africa, Indian, Malaysia, Philippines, and Australia.

·            Value of rectal biopsy in diagnosis of schistosomiasis demonstrated.

·            Baboon and grivet monkey confirmed as reservoir hosts of yellow fever virus in Sudan.

·            Documented urinary bladder cancer/schistosomiasis inter­relationships.

·            Pathology of hepatic involvement in schistosomiasis defined.

·            Publication of first key to snakes of Egypt.

·            Value of needle biopsy of spleen and liver in diagnosis of schistosomiasis demonstrated.

·            First isolations of phlebotomus fever virus from sandflies.

·            Effectiveness of Alcopar in treatment of hookworm infestation demonstrated.

·            Equines identified as natural hosts of West Nile fever virus.

·            Artificial medium developed to culture leishmania.

·            Classical treatise on the epidemiology of leishmaniasis in the Sudan.

·            Blood loss in Ancylostoma duodenale (Old World hookworm) infection first measured.

·            Quaranfil, Chenuda, and Nyamanini viruses isolated from ticks in the Nile Delta.

·            First isolation of Rickettsia conori and Coxiella burneti (Q Fever) in Ethiopia.

·            First evidence of Plasmodium ovale in Ethiopia.

·            First meningitis epidemic due to Group A sulfadiazine-resistant meningococcus reported; later occurred in the U.S.

·            Identification of primary and secondary vectors of malaria in the Ethiopian lowlands.

·            First authentication of Trypanosoma rhodesiensis (sleeping sickness) infection in Ethiopia; identification of vectors.

·            Near East equine encephalitis shown to be of toxic etiology, caused by ingestion of moldy corn.

·            Baboon established as model for relapsing fever research.

·            First documentation of bancroftian filariasis in Ethiopia.

·            Chloramphenicol confirmed as most effective therapy for typhoid fever and ampicillin demonstrated to be an effective alternate therapeutic agent.

·            A new drug combintion, trimethoprim and sulfamethoxazole, shown to be effective in therapy of typhoid fever; also used successfully in treating bacterial meningitis.

·            Enzyme-linked immunosorbent assay (ELISA) and counterimmuno­electrophoresis (CIEP) used successfully for rapid diagnosis of meningococcal meningitis.

·            Group A meningococcal vaccine shown to offer protection for up to 18 months in Egyptian subjects.

·            Multi-volume bibliography of ticks and tick-borne diseases.

·            Oxaminquin used successfully for previously untreatable complicated S. mansoni schistosomiasis

·            Monograph on Egyptian mammals, bringing together the data obtained on hosts, parasites, and disease relationships

·            Established a baboon model for immunological studies of S. haematobium infections

·            Described epidemiological and clinical features of the 1977-79 Rift Valley fever outbreak; made the first virus isolations; virus classified for the first time as belonging to the Phlebotomus group.

·            Monograph on the epidemiology of tick-borne Crimean-Congo hemorrhagic fever in Asia, Europe and Africa.



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