Epidemic of hepatitis E in a military unit in Abbotrabad, Pakistan.

An outbreak of hepatitis caused by hepatitis E virus (HEV) in Abbottabad, Pakistan was traced to fecal contamination of a water system. Of 109 men hospitalized with hepatitis, 104 (95%) had serologic evidence of acute hepatitis E (IgM antibody to HEV [anti-HEV]), three (3%) probably had acute hepatitis E (high titers of IgG anti-HEV without IgM), and two had acute hepatitis A. Among a subset of 44 men with acute hepatitis E from whom three serum specimens were obtained over a four-month period, the anti-HEV IgG geometric mean titers (GMTs) decreased from 1,519 during the outbreak to 657 at four months. The IgM anti-HEV was detected in 40 (91%) of 44 sera obtained at admission (GMT = 533 during acute disease), but in only six (14%) four months later. The prevalence of anti-HEV in this population before the outbreak was estimated to be 30%. The presence of IgG anti-HEV appeared to protect against clinical hepatitis or development of serologic evidence of new infection with HEV. This is the second major epidemic of hepatitis E in the Pakistani military confirmed by an anti-HEV enzyme-linked immunosorbent assay (ELISA). Evidence that pre-existing antibody as measured by this ELISA protects against disease is important for assessment of vaccine development.

Predictions of malaria vector distribution in Belize based on multispectral satellite data

Use of multispectral satellite data to predict arthropod-borne disease trouble spots is dependent on clear understandings of environmental factors that determine the presence of disease vectors. A blind test of remote sensing - based predictions for the spatial distribution of a malaria vector, Anopheles pseudopunctipennis, was conducted as a follow-up to two years of studies on vector-environmental relationships in Belize. Four of eight sites that were predicted to be high probability locations for presence of An. pseudopunctipennis were positive and all low probability site (0 of 12) were negative. The absence of An. pseudopunctipennis at four high probability locations probably reflects the low densities that seem to characterize field populations of this species, i.e., the population densities were below the threshold of our sampling effort. Another important malaria vector. An. darlingi, was also present at all high probability sites and absent at all low probability sites. Anopheles darlingi, like An. pseudopunctipennis, is a riverine species. Prior to these collections at ecologically defined locations, this species was last detected in Belize in 1946 (AU)

Preliminary observations on the changing roles of malaria vectors in southern Belize

A survey for larval and adult anopheles mosquitoes was conducted in Toledo District of southern Belize during August-September 1992. We surveyed for larvae in 145 habitats and conducted paired indoor-outdoor collections of adult mosquitoes landing on humans at 6 houses. In 1940-41, Kumm and Ram reported Anopheles darlingi females to be the most common Anophales mosquitoes inside houses and reported no specimens of Anophales vestitpennis in southern Belize. In our 1992 survey we found no An. darlingi mosquitoes either as adults or larvae. More An. vestitipennis females were captured indoors than outdoors, whereas most Anopheles albimanus and anophales apicimacula females were captured outdoors. All 3 species were represente occasionally in 145 collections of larvae from diverse habitats. Anophales vestitipennis now appears to be potentially important vector of malaria during the wet season in Toledo District (AU)

Initial report of a hepatitis investigation in rural Belize

In spring 1991, Belizian health officials expressed concern about a possible hepatitis outbreak in a banana farming district. A study was designed to identify cases and to address the serological prevalence of hepatitis virus markers. Three populations were studied: (i) persons meeting a clinical case definition for hepatitis; (ii) designated banana workers; and (iii) people in a random sample of households in the community. Information was collected using questionnaires and sera were collected for laboratory testing. This report presents the preliminary results of a study conducted in June 1991. Among people who met the clinical case definition, 24 percent of 42 tested had immunoglobulin M antibody to hepatitis B virus (HBV) core antigen (anti-HBc IgM). In the worker and household survey populations, 248 and 280 people, respectively, were tested for anti-HBc IgM. In each group, 4 percent were positive. HBV surface antigen was found in 37 percent of 43 clinical cases, 18 percent of workers, and 13 percent of people in the household survey. Among the 3 study populations, the prevalence of HBV core antibody (anti-HBc) ranged from 73 percent to 81 percent. Almost all tested persons had evidence of prior infection with hepatitis viruses A and B was widespread, but an aetiology could not be established for most of the clinical cases. However, the prevalence of hepatitis B markers in this population was very high compared to other reports from the Caribbean (AU)

Initial report of a viral hepatitis investigation in rural Belize - abstract

In spring 1991, concern was expressed in Belize about a hepatitis outbreak. A cross-sectional study was designed to address hepatitis prevalence in a farming district. Three populations were identified: anyone meeting a case definition for hepatitis, any designated worker, and a random sample of the community by household. Survey information was collected on the farm, household, and individual. Sera were collected for laboratory study. This study reports on the current findings from 509 sera collected in June 1991. There had been widespread exposure to hepatitis A(98 percent). New hepatitis was primarily due to hepatitis B(24 percent of clinical cases, 4 percent of people in the random household sample, and 5 percent of workers). In our total, 16 percent had hepatitis B surface antigen and were potential carriers, while 73 percent had evidence of past hepatitis C by our detection method, and delta particle was not present in any of the tested cases. Hepatitis E antibody was detected in two cases. One risk revolved around perceptions of good medical care, using injectable medications. (AU)