Protection of mice from fatal bubonic and pneumonic plague by passive immunization with monoclonal antibodies against the F1 protein of Yersinia pestis.

Monoclonal antibodies (MAbs) to the fraction 1 (F1) protein of Yersinia pestis protected mice against fatal pneumonic as well as bubonic plague from wild-type F1+ organisms. The rare isolation of a virulent F1- isolate from surviving animals supports earlier studies suggesting that improved vaccines should consist of immunogens to protect against F1- variants. The high degree of protection with IgG MAb suggests that secretory IgA is not required for protection from pneumonic plague.

Malaria among United States troops in Somalia.

PURPOSE: United States military personnel deployed to Somalia were at risk for malaria, including chloroquine-resistant Plasmodium falciparum malaria. This report details laboratory, clinical, preventive, and therapeutic aspects of malaria in this cohort. PATIENTS AND METHODS: The study took place in US military field hospitals in Somalia, with US troops deployed to Somalia between December 1992 and May 1993. Centralized clinical care and country-wide disease surveillance facilitated standardized laboratory diagnosis, clinical records, epidemiologic studies, and assessment of chemoprophylactic efficacy. RESULTS: Forty-eight cases of malaria occurred among US troops while in Somalia; 41 of these cases were P falciparum. Risk factors associated with malaria included: noncompliance with recommended chemoprophylaxis (odds ratio [OR] 2.4); failure to use bed nets (OR 2.6); and failure to keep sleeves rolled down (OR 2.2). Some patients developed malaria in spite of mefloquine (n = 8) or doxycycline (n = 5) levels of compatible with chemoprophylactic compliance. Five mefloquine failures had both serum levels > or = 650 ng/mL and metabolite:mefloquine ratios over 2, indicating chemoprophylactic failure. All cases were successfully treated, including 1 patient who developed cerebral malaria. CONCLUSIONS: P falciparum malaria attack rates were substantial in the first several weeks of Operation Restore Hope. While most cases occurred because of noncompliance with personal protective measures or chemoprophylaxis, both mefloquine and doxycycline chemoprophylactic failures occurred. Military or civilian travelers to East Africa must be scrupulous in their attention to both chemoprophylaxis and personal protection measures.

Determination of fifty percent inhibitory concentrations (IC50) of antimalarial drugs against Plasmodium falciparum parasites in a serum-free medium.

Plasmodium falciparum chemosensitivity to the various antimalarial drugs is presently determined in the laboratory by setting up multiple microcultures of the parasite and estimating the amount of growth inhibition caused by known concentrations of drug. Parasite growth inhibition is assessed either by microscopy, radiolabeled substrate uptake, or calorimetrically. The obligate requirement for serum in this assay presents difficulties in the direct comparison of results among laboratories. We now have evidence that antimalarial drug sensitivity assays can be reliably performed in a serum-free medium. The overall comparison of 50% inhibitory concentration (IC50) values obtained with serum-free media (bovine albumin, Cohn fraction V [BAM] and BAM combined with glucose and lipids-cholesterol-rich mixture) and those obtained in serum-supplemented medium was r = 0.56; n = 60; P < 0.01.

Threat of hepatitis E virus infection in Somalia during Operation Restore Hope.

In support of Operation Restore Hope, the United States military established a diagnostic laboratory for infectious diseases, the Joint Forward Laboratory, in Mogadishu, Somalia. Because sporadic hepatitis due to unknown causes was a frequent problem, staff members of the Joint Forward Laboratory evaluated 31 Somalis, five displaced Ethiopians, and three Western relief workers who had acute clinical hepatitis. Patients lived in multiple locations in Somalia--Mogadishu, Baidoa, and Merca--and became ill between December 1992 and February 1993. IgM antibody to hepatitis A virus was found in one English relief worker, and IgM antibody to hepatitis E virus was found in 20 (65%) of 31 Somalis, two (40%) of five Ethiopians, and two (67%) of three Western relief workers. No patient had evidence of acute hepatitis B, malaria, yellow fever, or other arbovirus infections. These data indicate that hepatitis E virus--the major cause of enterically transmitted non-A, non-B hepatitis--was a common cause of acute sporadic hepatitis in Somalia during the initial stages of Operation Restore Hope.

Outbreak of fatal illness among captive macaques in the Philippines caused by an Ebola-related filovirus.

Following the detection of an Ebola-like virus in cynomolgus macaques recently imported into the United States from The Philippines, studies were initiated to document transmission at export facilities located in the latter country. At one export facility, 52.8% of 161 monkeys that died over a 2.5-month period were shown to be infected with this virus using an enzyme-linked immunosorbent assay to detect antigen in liver homogenates. A case fatality rate of 82.4% was documented for the infected monkeys. The initial anti-viral antibody prevalence among the captive macaques at this facility was 25.9% (indirect fluorescent antibody titer greater than or equal to 1:16). Followup documented infection of 24.4% of initially seronegative animals and 8.7% of initially seropositive monkeys. Being held in a gang cage versus a single cage was found to be a significant risk factor for subsequent virus infection, and the presence of IFA antibody was shown to predict protection. This study documents unequivocally for the first time the presence of an Ebola-related filovirus in Asia.

The epidemiology of hepatitis C virus antibody in Yemen.

A cross-sectional survey of 348 subjects without evidence of liver disease was conducted to investigate the prevalence and risk factors for hepatitis C virus antibody (anti-HCV) seropositivity in the Yemen Arab Republic. The mean age of study subjects was 28.7 years (range 3-80), and 61% were males. Using commercial enzyme-linked immunosorbent assays (ELISA), 6.0% (95% confidence interval [CI] 3.8-9.1) of subjects were anti-HCV-positive, 13.5% were hepatitis B surface antigen-positive (HBsAg-positive), and 51.4% were positive for at least one serologic marker of prior hepatitis B infection. Nine (2.6%; 95% CI 1.2-4.9) of the 21 ELISA-positive sera were confirmed to be anti-HCV positive by a recombinant immunoblot assay. Anti-HCV seropositivity was significantly associated with age (odds ratio [OR] 2.0 for each 10-year increase in age) and prior surgery (OR 10.1), but was not associated with a history of prior blood transfusion or markers of hepatitis B infection. These preliminary data suggest that hepatitis C may pose a substantial health threat in Yemen.

Antibodies to human T lymphotropic virus type I in a population from the Philippines: evidence for cross-reactivity with Plasmodium falciparum.

Residents of two areas in the Philippines were tested for human T lymphotropic virus type I (HTLV-I): Napsan, a site endemic for malaria, and a nonmalarious site, Bacolod. By ELISA, 30% of the 1743 Napsan residents were positive. Western blot immunoreactivity with two or more HTLV-I proteins was present in 81% of the ELISA positives; however, there was no reactivity with the env proteins. The frequency of this indeterminate immunoreactivity increased with the malaria antibody titer. None of the 200 Bacolod sera were Western blot immunoreactive. In competitive serologic assays, an HTLV-I lysate blocked the HTLV-I immunoreactivity of the Napsan sera but did not reduce malaria antibody. A Plasmodium falciparum lysate blocked both the HTLV-I and malaria immunoreactivity of the Napsan sera. These results show that indeterminate HTLV-I immunoreactivity can be caused by P. falciparum antibody. Serosurveys conducted in malaria endemic areas should consider this possibility.

Travelers' diarrhea among United States military personnel during joint American-Egyptian armed forces exercises in Cairo, Egypt.

A study was conducted of travelers' diarrhea in a United States military population on deployment in Cairo, Egypt, during July and August 1987. Acute diarrhea requiring medical attention developed in 183 (4%) of 4,500 troops. A possible etiologic agent was identified in 49% of all diarrhea cases. Enteric pathogens associated with cases of diarrhea included: Enterotoxigenic Escherichia coli (17% ST-producers, 13% LT-producers, and 3% LT/ST-producers); Shigella (9%); Campylobacter spp. (2%); Salmonella (2%); and Vibrio cholerae non-01 serogroup (2%). Other enteric pathogens isolated from one episode each of diarrhea included Aeromonas hydrophila group, Plesiomonas shigelloides, and Bacillus cereus. Yersinia enterocolitica, enteroinvasive E. coli, intoxications by Clostridium perfringens and Clostridium difficile, and pathogenic enteric parasites were not found in any of the 183 patients with diarrhea. A survey of military personnel not requesting medical care indicated that up to 40% of troops may have had diarrhea during this deployment. Acute gastroenteritis is a potential cause of substantial morbidity in U.S. military personnel deployed to Egypt.

Serosurvey of prevalence of human immunodeficiency virus amongst high risk groups in Port Sudan, Sudan.

During October, 1987, 593 sera were collected from risk groups in Sudan's only major deepwater port, Port Sudan. The risk groups included prostitutes, lorry drivers and prisoners. A large proportion of the study participants practised high risk behaviour which included sexual promiscuity, medical treatment by injection, scarification and tattooing. Despite high risk behaviour and evidence of a high prevalence of hepatitis B infection, a virus transmitted in a manner similar to HIV, no study participants were positive for HIV infection. This data suggests that the prevalence of HIV infection amongst high risk groups in Port Sudan is very low. These findings confirm a lack of clinical cases of AIDS in hospitalized patients in Port Sudan and the small number of reported cases in other areas of northern Sudan.

PIP: The high prevalence of hepatitis B markers in the Sudan (up to 80% of those surveyed) suggests the potential for a rapid spread of human immunodeficiency virus (HIV) since both viruses are transmitted in similar ways. Although clinical cases of acquired immunodeficiency syndrome (AIDS) have not been reported from Port Sudan, southern Sudan borders on several countries with a high prevalence of HIV infection. Sudan's National AIDS Committee plans a series of surveys to determine the prevalence of HIV infection in high risk groups and the general population in several geographic regions. The 1st such survey was conducted in Port Sudan in 1987 among 593 high-risk individuals (203 prostitutes, 103 lorry drivers, 118 prisoners, and 169 in mixed occupations). The study population included 330 males and 263 females. About half of the participants were married and in the 21-30-year age group. Over 75% had been exposed to hepatitis B and 76% had been treated for malaria, largely through injection. Overall, the incidence of non-sex-related risk factors for HIV infection among Port Sudan subjects was: injection, 48%; scarification, 40%; and tatoos, 38%. 32% reported a prior history of a sexually transmitted disease. 71% of the males had used prostitutes. Surprisingly, no study participants were positive for HIV infection. This finding presumably reflects Port Sudan's geographic isolation from other Central and East African countries with large numbers of HIV-positive individuals. On the other hand, Port Sudan is the site of importation of all goods by sea into the country and many people from other African and Arab countries are associated with the seaport. Thus, once the HIV virus is introduced by infected persons from other areas, the risk factors suggest the potential for rapid transmission.

HIV infection surveillance in Mogadishu, Somalia.

A group of 89 prostitutes and 45 patients attending sexually transmitted disease clinics in Mogadishu, Somalia were examined for evidence of HIV infection. Both groups reported more than 1 sexual partner routinely and had sexual contacts with prostitutes. There was a significant amount of sexually transmitted diseases (STDs) in these two groups, with 11.2% and 6.7% respectively being culture positive for N. gonorrhoea. Among the prostitutes, 28.1% were positive for antibodies to T. pallidum while only 4.4% of the STD patients were positive. One isolate of N. gonorrhoea was resistant to penicillin. All study participants were negative for antibodies to HIV suggesting an extremely low prevalence of HIV in high risk behaviour groups in the capital city of Somalia.

PIP: 89 prostitutes and 45 men attending the sexually transmitted disease (STD) clinic in Mogadishu, Somalia, were tested for HIV (human immunodeficiency virus) with the Abbott ELISA (enzyme-linked immuno-sorbent assay) test, cultured for gonorrhea, and screened for syphilis. There were no sera positive for HIV. 11% of the prostitutes and 7% of the men had positive gonorrhea cultures; 28% of the prostitutes and 4% of the men were positive for syphilis; 1 of the men had penicillin-resistant N. gonorrhoea with a beta-lactamase test. An epidemiological questionnaire was administered to the subjects. Most were aged 20-29; 67% were married; 80% of the men and 22.5% of the women were soldiers. 40% of the men reported use of prostitutes. Stated numbers of sexual contacts were 1.87/week for the prostitutes, and 1.51/week for the men. Data were also reported on occupations, recent injections, immunizations, intravenous drug use, surgery, blood transfusions and scarification.

A seroepidemiological survey of viral hepatitis in the Yemen Arab Republic.

During February 1988 a seroepidemiological survey of hepatitis A, B and D was performed in the Yemen Arab Republic. 879 sera were collected from 4 different areas; Sanaa, Hajja, Hodeidah and Taiz. The prevalence of hepatitis B surface antigen (HBsAg) was 12.7% (112/879) and some marker of hepatitis B infection was found in 45.5% (399/879) of study subjects. Only 2 (1.8%) of the 112 HBsAg positives were positive for antibody to delta hepatitis, and 9.7% (9/93) were positive for hepatitis B e antigen (HBeAg). Univariate analysis showed age, sex, qat chewing, blood transfusion, surgery and a past history of jaundice to be associated with hepatitis B infection. Using multivariate logistic regression analysis only, age (odds ratios 1.37 for HBsAg carriers and 1.51 for seropositives), a past history of jaundice (odds ratio 1.42), and combined history of blood transfusion and surgery (odds ratio 2.76) were independent predictors of infection. Hepatitis B appears to be a major health concern in the Yemen Arab Republic.

Hepatitis B and HIV in Sudan: a serosurvey for hepatitis B and human immunodeficiency virus antibodies among sexually active heterosexuals.

A serosurvey was conducted in Port Sudan and Suakin, Sudan in October and March 1987 to determine the prevalence and risk factors associated with the transmission of hepatitis B, human immunodeficiency virus type 1 (HIV-1), and syphilis among sexually active heterosexuals on the coast of Sudan. A total of 536 subjects, including 202 female prostitutes, 95 long-distance truck drivers, 103 soldiers, 72 Ethiopian refugees, and 54 Sudanese outpatients, were enrolled in the study. Seventy-eight percent (202/259) of the female study subjects were engaged in prostitution, and 57% (157/277) of the men admitted to prior sexual relations with prostitutes. Serologic markers for hepatitis B and syphilis were detected in 68% and 17% of the entire study population, respectively. In contrast, antibody to HIV-1 was detected in none of the 536 sera tested. Risk factors found to be independently predictive of hepatitis B infection by multivariate analysis included prostitution, positive serology for syphilis, and a history of anti-schistosomal therapy. The absence of HIV-1 infection among the prostitutes enrolled in this study is in marked contrast to the current AIDS epidemic in neighboring sub-Saharan countries, suggesting that HIV-1 has not been widely introduced on the coast of Sudan. The high prevalence of serologic markers to hepatitis B and syphilis, however, indicates a potential for HIV-1 in this region.

Comparative trial of erythromycin and sulphatrimethoprim in the treatment of tetracycline-resistant Vibrio cholerae O1.

The efficacy of the 2 antimicrobial compounds, erythromycin and trimethoprim-sulphamethoxazole, were compared in the treatment of the clinical symptoms of cholera and the eradication of Vibrio cholerae O1 organisms from the stools of patients infected with tetracycline-resistant strains. 47 patients with a clinical diagnosis of cholera, without prior antibiotic therapy, were included in the trial and received either erythromycin, trimethoprim-sulphamethoxazole, or a placebo twice daily. The mean number of vibrios per gram of stool decreased from 5.2 x 10(8) +/- 0.3 per ml to 0 within 36 h of admission following either erythromycin or trimethoprim-sulphamethoxazole therapy, while organisms persisted in placebo-treated controls for more than 7 d. Clinically there was a significant reduction in the number of diarrhoeal stools per day and duration of diarrhoea in the erythromycin-treated group compared with the placebo-treated controls. During the study an isolate resistant to trimethoprim-sulphamethoxazole but sensitive to erythromycin was obtained. As an adjunct to oral rehydration therapy, erythromycin may serve as an effective alternative treatment for cholera, especially in areas where trimethoprim-sulphamethoxazole resistance may be emerging.

AIDS: the situation in Mogadishu during spring 1987.

To determine if AIDS was present in Mogadishu during spring 1987, we screened hospital patients for the presence of diseases compatible with acquired immunodeficiency. Twenty-nine such patients were identified and had their serum tested for antibodies to HIV by standard serologic techniques. All these sera were negative for HIV antibodies. During the same time, at the Mogadishu clinic for sexually transmitted diseases, 48 individuals were examined for evidence of HIV infection. No patient had clinical signs compatible with AIDS, but one serum was anti-HIV antibodies positive in both the ELISA and western blot assay. We conclude that there was no clinical AIDS in Mogadishu in early 1987 and that prevalence of HIV infection in high risk individuals was very low.