The American Journal of Tropical Medicine and Hygiene - Volume 38, Issue 3, 1988

Mass drug administration via 3 modes of delivery reduced the incidence and prevalence rates and intensity of Brugia malayi infection in 3 rural villages in the Bengkoka Peninsula, Sabah, in 1982–1983. A dosage of 6 mg diethylcarbamazine citrate (DEC-C)/kg body weight was administered either daily or weekly (total of 6 doses, 36 mg/kg body weight), and impact on B. malayi cases were comparable in the 3 villages. A total of 384 people participated in the DEC-C regimens, and all pregnant women and children under 2 years were excluded from the study. Bekessy's method of estimation of incidence and recovery rates was applied to data on B. malayi microfilaremia before drug administration. Treatment with DEC-C by any of the 3 modes of delivery drastically reduced the number of episodes of patent microfilaremia, incidence and prevalence, and median microfilarial density. Reduction was sustained for at least 18 to 24 months after treatment.

This study was designed to reexamine the efficacy of diethylcarbamazine for bancroftian filariasis with special reference to changes in serum parasite antigen levels and antifilarial antibody titers after treatment. Patients with asymptomatic microfilaremia were treated with 6 mg/kg diethylcarbamazine daily for 12 days. Microfilaria counts fell dramatically after treatment, as expected. IgG antibody titers to adult and microfilarial antigens of B. malayi were increased 1 month after treatment in most patients. Titers fell slowly to or below pretreatment levels, but remained positive during subsequent months. Parasite antigen levels, measured by monoclonal antibody-based enzyme immunoassay, decreased to 72%, 58%, 53%, and 48% of pretreatment values 1, 3, 6, and 12 months after diethylcarbamazine treatment, respectively. Parasite antigen levels decreased similarly in subjects with and without residual microfilaremia after treatment. These results suggest that diethylcarbamazine has only partial macrofilaricidal activity against W. bancrofti with this dosage schedule. The sustained, impressive reductions in microfilaria counts after treatment despite significant persistence of parasite antigenemia may be explained by sublethal effects of the drug on adult worms. We believe that parasite antigen detection represents a valuable new approach for monitoring the efficacy of antifilarial drug therapy which we hope will lead to improved use of existing drugs and aid in the evaluation of new drugs for filariasis.

Laboratory-derived Simulium yahense and S. sanctipauli females were used to produce large numbers of Onchocerca volvulus infective stage larvae (L3) for use in assessing the possible chemoprophylactic potential of ivermectin in the chimpanzee model. Engorgement rates and subsequent post-prandial survival were correlated with the time at which adult flies were offered a carbohydrate source following emergence and the age of flies that fed on microfiladermic volunteers.

A painless lump in the breast in a 43-year-old Chinese woman was found on surgical excision to be a cysticercus presumed to be that of Taenia solium. Routine investigations failed to reveal infection at any other site.

In South America programs to control hydatidosis caused by Echinococcus granulosus include the active search for asymptomatic patients through population surveys for the detection of antibodies against arc 5 antigens using the double diffusion arc 5 test (DD5). Though simple to perform and highly specific, DD5 is not practical for population studies due to the time lapse between testing and receiving results. This work evaluates the application of an enzyme immunoassay to screen sera for subsequent processing using DD5. The efficiency of an enzyme immunoassay screening/DD5 confirmation scheme vs. DD5 alone was compared within the framework of a control program. A total of 5,839 sera from residents of endemic areas was processed and 47 hydatid patients were detected by both schemes. The proposed enzyme immunoassay identified all sera having antibody activity against arc 5 antigens detectable by DD5 and ruled out 95.3% of sera which tested by DD5 would have produced negative results.

Leukocyte subsets present in the granulomatous response produced after the inoculation of a mixture of Mycobacterium leprae and BCG in lepromatous leprosy patients were characterized in situ using monoclonal antibodies and an immunoperoxidase technique. The granuloma produced after M. leprae-BCG inoculation showed a distribution pattern similar to tuberculoid granulomas. T lymphocytes bearing the CD8 phenotype (T cytotoxic/suppressor) were sequestered to the periphery of the epithelioid tubercles and T helper-inducer CD4+ lymphocytes were distributed throughout the infiltrate. Langerhans cells CD1 + were increased in the epidermis, and in dermis they were localized mainly in the mantle surrounding the granuloma. Most of the dermal infiltrate produced after the inoculation or M. leprae-BCG expresses the HLA-DR antigen. Similarly, most keratinocytes were also positive to this MHC antigen. The granulomatous response to BCG was similar to the inoculation of a mixture of M. leprae-BCG, however acid-fast bacilla were still present. The inoculation of M. leprae produced a macrophage granuloma with no clearing of the bacilla which resembles the lepromatous leprosy granuloma.

An outbreak of shigellosis associated with swimming at a human-made lake during the Labor Day weekend occurred in Los Angeles County in 1985. Sixty-eight persons had onset of diarrheal illness within 1 week following exposure at the recreational site. Thirty-three of these cases were culture-confirmed as shigellosis (29 Shigella sonnei, 4 Shigella boydii). Fifteen persons were hospitalized. Illness was highly associated with water contact, specifically swallowing water while swimming (P < 0.001) and age < 15 years (P < 0.001). Water samples from the swimming area had high fecal coliform counts; however, dye testing showed no evidence of sewage contamination. Direct bather contamination of the swimming area may have occurred in the context of large crowds, inadequate restroom facilities, poor water exchange, and the absence of a mechanism of disinfection.

The effects of tourniquet application were prospectively studied in 36 hospitalized patients who developed neurotoxic symptoms after bites by the Philippine cobra (Naja naja philippinensis). Tourniquets had been applied in 94% of cases and delayed the onset of symptoms. Four patients were asymptomatic prior to the release of their tourniquet and in 11 patients symptoms worsened precipitously. Most importantly, 4 patients developed complete respiratory paralysis requiring artificial ventilation on its removal. Medical personnel seeing patients after a possible cobra bite should remove any tourniquet very gradually with both specific therapy and ventilatory support at hand. We recommend tourniquet application in the Philippines only after the bite of a definitely identified cobra and when removal can take place under controlled hospital conditions.

In some areas of endemic trachoma, muscoid flies may play a significant role in transmission of this serious eye infection. A simple and practical method of quantifying the relative household density of synanthropic flies has been developed for use in epidemiological field surveys. The method uses two boards moistened with a 10% sucrose solution. The fly scores showed good reproducibility at the same sampling site during the day and on different days. The only flies identified were Musca sorbens, showing their local density and a significant association of this fly with the presence of inflammatory trachoma in children.

An outbreak of icteric non-A non-B (NANB) hepatitis occurred in a residential community of urban Karachi, Pakistan, from August 1986 through October 1986. Of the 114 cases reported from this community during the 1986 calendar year, a clustering of 85 cases was seen during the above period. Twenty-seven percent of 226 households and 9% of 1,250 individuals were affected. Five persons were hospitalized and 1 death occurred in a young pregnant woman. Cases occurred predominantly in the ≤29-year-old age group (72%), with a male: female ratio of 1.8:1. Thirty-four cases occurred singly within households, while in 28 households multiple cases were seen. Analysis of the epidemic curve and intervals of onset of multiple cases within households suggested prolonged common source exposure rather than secondary person-to-person transmission. No single water source was implicated but a contaminated municipal supply was presumed. Information collected from several other communities and from a university hepatitis reference laboratory suggested that the outbreak was part of a larger urban epidemic of NANB hepatitis. Based upon this investigation and data from recently published reports, it is concluded that NANB hepatitis is endemic in Pakistan.

A house-to-house survey was carried out to determine the prevalence of poliomyelitis. During the survey 37,219 households were visited and 17,941 children 5–9 years old were found. Of 231 lame children, lameness compatible with paralytic poliomyelitis was found in 131, of these 91% had their condition before the age of 3 years. Nineteen percent ndeded a stick support for walking while 12% were unable to walk even with support. This problem was more common in rural populations. The prevalence of paralytic poliomyelitis was 7.3/1,000 children 5–9 years old.

Hantaan, Seoul, and Puumala viruses were transmitted to 12–16-week-old female Wistar Rattus norvegicus by inhalation. The rodent infectious dose for each virus by intramuscular inoculation and by inhalation was determined, as was the infectious dose for Vero E-6 cells by direct plaque assay.

The sensitivity and specificity of an enzyme-linked immunosorbent assay (ELISA), absolute numbers of T-helper cells, and T-helper: T-suppressor cell ratios were compared in asymptomatic controls and IgG Western blot-confirmed patients with the acquired immune deficiency syndrome (AIDS) in Kinshasa, Zaire, between August 1984 and May 1985. Two hundred sixteen (97.7%) of 221 IgG western blot-positive AIDS patients and 4 of 97 (4%) controls were ELISA-positive, 3 of whom were Western blot-positive. The sensitivity and specificity of the ELISA was 97.7% and 99.0%, respectively, compared to Western blot results. Detection of the human immune deficiency virus using absolute number of T-helper cells (<400 cells/mm3) was as sensitive (98.2%), but less specific (90.7%). A T-helper: T-suppressor ratio of <0.9, had a sensitivity of 97.3%, and specificity of 94.8%. The ELISA test had the highest predictive value and greatest utility in an African clinical setting for detecting HIV infected patients were a wide range of other immunocompromising diseases are seen.

Developments in Veterinary Virology: Avian Leukosis, edited by G. F. De Boer. x + 292 pages, illustrated. Kluwer Academic Publishers Group, P.O. Box 989, 3300 AZ Dordrecht, The Netherlands. 1987. $70.00.

Community Health Aide/Practitioner Manual, by Robert D. Burgess. viii + 464 pages, illustrated. Alaska Area Native Health Service, 1345 Rudakof Circle, Suite 206, Anchorage, Alaska 99504. 1987. $34.00.

WHO Expert Committee on Onchocerciasis, Third Report. Technical Report Series, No. 752, by the World Health Organization. 167 pages, illustrated. World Health Organization, 1211 Geneva 27, Switzerland. 1987. $14.40, paperbound.

Vector Control in Primary Health Care, Report of a WHO Scientific Group. Technical Report Series, No. 755, by the World Health Organization. 61 pages. World Health Organization, 1211 Geneva 27, Switzerland. 1987. $5.40, paperbound.

Plant Molluscicides, edited by Kenneth E. Mott. xi + 326 pages, illustrated. Published for UNDP/World Bank/WHO by John Wiley & Sons, Inc., 605 Third Avenue, New York, New York 10158. 1987. Paperbound.

A recent Journal article by Martinez and others, concerned the determination of the efficacy of pentavalent antimony, the primary agent for leishmaniasis, against Leishmania braziliensis and L. donovani amastigotes in a human macrophage cell line (U937). The dose of Pentostam (sodium stibogluconate) expected to 50% inhibit growth (ED50) of both species was “10 and 6 ng/ml, respectively.” Doses >100 ng/ml were not tested and there was no dose that inhibited >70% of parasite growth.

In the Discussion section of this article, the authors state that “the growth inhibition of L. b. braziliensis and L. donovani (Khartoum) by sodium stibogluconate is similar to that reported in other established systems.14” Reference 14 is work of our group. As the title indicates, it concerns the antileishmanial activities of experimental purine analogs, not of Pentostam. However, we have reported the activity of Pentostam against L. tropica (now called L. major) and L. donovani amastigotes in human monocyte-derived macrophages in other work.