Seroprevalence of hepatitis E virus antibodies in different human populations of Cameroon.

Hepatitis E virus (HEV) is a major cause of acute hepatitis worldwide. HEV infection is self-limiting, but fulminant hepatitis may occur with higher mortality rates. The aim of this study was to determine the seroprevalence of the HEV in three different populations in Cameroon and to assess alimentary risk factors of infection. A total of 903 individuals including 450 elderly people, 183 pregnant women, and 270 HIV-infected patients were enrolled during 2009-2015. All sera obtained were tested for the presence of anti-HEV antibodies with commercial enzyme-linked immunosorbent assay kits. The association between initial anti-HEV status and potential risk factors was assessed. Out of the 903 samples, 22.0% (199/903) were positives for anti-HEV immunoglobulin M (IgM), 5.8% (52/903) for anti-HEV IgG, and 3.5% (32/903) for both. The seropositivity for IgM was 7.0%, 13.1%, and 34.7%; meanwhile, the seropositivity for immunoglobulin G was 8.5%, 3.3%, and 5.1%, in HIV-infected patients, pregnant women, and the elderly population, respectively. Both antibodies were detected simultaneously in 2.2%, 1.6%, and 5.1% in HIV-infected patients, pregnant women, and the elderly population, respectively. No risk factors were significantly associated with HEV infection in these populations. This study showed a high prevalence of anti-HEV antibodies in three different populations in Cameroon.

Assessment of the neutralizing potency of antisera raised against native and γ-irradiated Naja nigricollis (black-necked spitting cobra) venom in rabbits, concerning its cardiotoxic effect.

The present study was designed to prepare a specific safe antiserum for Naja nigricollis using γ-irradiated (1.5KGy and3KGy) venoms. Rabbits were used for active immunization using irradiated venoms (1.5 and 3 kGy) as a toxoid, mice were used for determination of LD50 post immunization and the rats were used for neutralization of the cardiotoxic effect of venom. Results of the immunodiffusion test indicated that the sera of rabbits raised against non-irradiated, 1.5- and 3-kGy γ-irradiated venom, had the same results of precipitin bands. A significant inhibition of phospholipase A2 activities was obtained when neutralized with native, γ-irradiated (1.5KGy and3KGy) venoms. On the other hand, preincubation of the venom ½ LD50 (0.154 mg/kg i.p.) with each antiserum (non-irradiated or irradiated venom) at 37°C for 1 h in a ratio (1:4) produced a significant reduction in the values of creatine kinase and creatine kinase isoenzyme-MB. However, significant elevation in aspartate aminotransferase level and no change in lactate dehydrogenase level were observed. So the results of this study indicated that the irradiated venom treatment reduces the cardiotoxic effect of venom in immunized immunization animals for preparing vaccines.

Effect of the pre-incubation storage period of hatching eggs on the hatchability and post-hatching growth of local chickens under tropical conditions.

In order to study the effect of the storage period, 2400 hatching eggs from hens in the Tanzanian coastal region were stored for 0 to 15 days under room conditions of temperature and humidity. On the 16th day of a collection period with daily additions, the incubation of 50 eggs each was started. At hatching time, the number of healthy chicks hatched from each storage period treatment was counted. Also studied was the growth of the hatched chicks for the first three weeks of their life. A highly significant negative correlation (-0.98) was observed between the pre-incubation storage period and the hatchability of eggs. The regression coefficient was found to be -5.3. This means that hatchability declined by an average of 5.3% for each day the eggs had been stored. Prolonged storage of hatching eggs also affected the post-hatching growth performance of these chicks. The adverse effect disappeared, however, with increasing age of the chicks. It is recommended that hatching eggs should not be stored under ordinary room conditions in the tropics for more than 7 days prior to hatching.