Laboratory diagnosis of acute measles infections in hospitalized children in Zambia.

Laboratory diagnosis of measles infection is rarely performed in developing countries and tends to depend on clinical symptoms alone. We evaluated detection of immunoglobulin M (IgM) antibodies for confirmation of acute measles infection in Zambia. In 149 hospitalized children with clinical diagnosis of measles, IgM antibodies were detected in 88.6% (132/149). The IgM-positive rate increased with time after onset of skin rash and all samples were positive after 4 days. In addition to IgM antibody test, virus isolations from throat swabs using B95a cells were also performed. These were positive in only 20.9% (14/67), and both IgM and virus isolation in combination increased the positive rate to 92.5% (62/67). Vaccinated children had higher neutralizing (Nt) antibody responses and, among IgM-negative patients, all 4 vaccinated children had high Nt antibodies while all 10 unvaccinated children had negative or low Nt results. The IgM antibody test was proved to be a sensitive method for laboratory confirmation of measles virus infection in developing countries.

Prevalence of hepatitis B antigens in human immunodeficiency virus type 1 seropositive and seronegative pregnant women in Zambia.

PIP: During April-October 1992 in Zambia, 1861 pregnant women attending prenatal clinics in 3 urban health centers in Lusaka and 5 district hospitals in various provinces were recruited to examine the association between HIV infection and hepatitis B virus (HBV) infection. 340 (18.3%) tested positive for HIV infection. HIV-positive pregnant women were more likely to test positive for the hepatitis B surface antigen (HBsAg) than were HIV-negative pregnant women, but the difference was not significantly different (7.1% vs. 5.4%; p = 0.23). On the other hand, among the HBsAg-positive pregnant women, HIV- infected women were more likely to test positive for hepatitis B e antigen (HBeAg) than were HIV-negative women (25% vs. 12.3%; p 0.05), suggesting more HBV replication in HIV-infected people. Only women younger than 30 tested positive for HBeAg. If HIV does indeed facilitate HBV replication and increases its rate of vertical transmission, the HBV epidemiological pattern in sub-Saharan African could change. Further studies focusing on the epidemiological impact of HIV on HBV infection in sub-Saharan Africa are needed.^ieng

Hepatitis B virus infection among pregnant women in Zambia.

The prevalence of hepatitis B virus (HBV) markers was studied in pregnant women attending antenatal clinics in Zambia. A total of 2,098 pregnant women were recruited into the study at three urban health centres in Lusaka, the capital city and four district hospitals in rural areas of different provinces of Zambia. The overall prevalence of HBsAg was 6.5% (137/2,098), and HBeAg was present in 16.1% (22/137) of those positive for HBsAg. Antibody positive rate (HBsAb and/or HBcAb) was 51.3% in randomly selected HBsAg negative samples. HBsAg positive rate varied between 3.3% and 13.6% in each study sites. Prevalence for both HBsAg and antibodies to HBV were significantly higher in rural areas (district hospitals) than in urban areas (urban health centres in Lusaka). These data show that although HBV is endemic in Zambia, the prevalence varies from region to region.

Measles infection in hospitalized children in Lusaka, Zambia.

A 2-year hospital-based survey of measles infections were carried out at the University Teaching Hospital (UTH) in Lusaka, Zambia from January 1992 to December 1993. During this period, a total of 1066 children with a clinical diagnosis of measles were admitted to the paediatric isolation ward at UTH. Measles cases were seen throughout both 1992 and 1993. However, there was a peak from September to December, 1992. The number of cases decreased with age, and 370 (34.7%) were under 1 year old. It is noteworthy that 203 (19.0%) were less than the 9 months of age which is the recommended time for measles vaccination in Zambia. The overall case fatality rate was 12.6%, and was higher in children aged 0-3 years (14.3%) than in those aged 4 years and above (6.7%). Measles vaccination status could be checked from the child's immunization card for 343 measles cases over 9 months of age, 118 (34.4%) of these having previously received measles vaccine. Vaccinated children had a significantly lower case fatality rate (6.4%) than the unvaccinated group (17.0%). This suggests that while measles vaccine cannot prevent infection, it can reduce the severity of infection.

PIP: During January 1992-December 1993, in Zambia, 1066 children aged 0-15 were admitted to the pediatric isolation ward with measles at the University Teaching Hospital in Lusaka. Measles cases peaked during September-December 1992, which comprised all of the 1992 hot dry season and the beginning of the hot rainy season. There were more measles cases in 1992 than in 1993 (831 vs. 235). 86.9% of all measles cases were 0-5 years old. The overall case fatality rate was 12.6%. Measles cases aged less than 3 were more likely to die than older children (14.3% vs. 6.4%; p = 0.025). The researchers had access to immunization cards in 330 measles cases aged 10 months or older. 34.4% had received measles vaccine earlier. The vaccine efficacy in this group was 44.3%. Vaccinated cases were less likely to die than unvaccinated cases (6.8% vs. 17%; p = 0.009). These findings indicate that the measles vaccine used had a low efficacy, but it minimized the severity of measles and protected against death.

Rotavirus gastro-enteritis in hospitalized children with acute diarrhoea in Zambia.

The clinical and epidemiological aspects of rotavirus diarrhoea were studied in hospitalized children with acute diarrhoea in Lusaka, Zambia. Two hundred and fifty-six (24.0%) of 1069 children admitted to the study were shedding rotavirus. The rotavirus-positive rate was highest in children less than 1 year of age (37.0%) and it was also high in those less than 6 months old. Rotavirus diarrhoea was seen throughout the year with a higher rotavirus-positive rate in the dry season. In rotavirus-positive diarrhoea patients, more children were dehydrated (82.4%) than in the rotavirus-negative group (56.2%). Rotavirus infection was more common in the children with normal nutritional status (27.6%, 162/588) than in those with malnutrition (19.3%, 93/482). The associated case fatality rate in the rotavirus-positive group was 6.4%, significantly less than in the rotavirus-negative group (OR 0.44, 95% CI 0.24-0.79), and mortality cases were seen only in children less than 2 years old.

Association of rotavirus and human immunodeficiency virus infection in children hospitalized with acute diarrhea, Lusaka, Zambia.

In Lusaka, Zambia, rotavirus (RV) and human immunodeficiency virus (HIV) infection commonly coexist; 132 (25%) of 537 consecutively studied infants < 5 years old hospitalized with diarrhea were positive for both viral infections. Infants with RV infection were younger than those who were RV-negative (P > .05), and infants with both viruses more frequently experienced dehydration (P < .05). HIV-infected children more often exhibited respiratory symptoms on admission to the study (P < .0001) and were more frequently underweight (P < .0001) than were HIV-negative children, independent of RV infection. The mortality rate was highest in HIV-positive infants (P < .05), and coinfection with RV did not increase the risk of fatality. This study demonstrates that while RV and HIV infections commonly coexist in one region of Africa, RV infection is no more common nor is the illness more severe in HIV-positive infants.