Effect of frozen period on the chemical, microbiological and sensory quality of frozen Tilapia fish (Sarotherodun galiaenus).

The study was designed to investigate the effect of duration of frozen storage on the chemical, microbiological and sensory profile of Tilapia fish (Sarotherodun galiaenus) collected from a research pond of the Agricultural Development Project, Akure, Nigeria, subjected to sixty days of frozen storage and analyzed at intervals of ten days. Protein content (%) ranges from 43.70 +/- 1.17-60.65 +/- 2.40. Protein decreases with increasing duration of frozen storage with the fresh samples (not frozen) having the highest protein content (60.65 +/- 2.40) while the least (43.70 +/- 1.17) was recorded for fish samples that were frozen for sixty days. Similar results were obtained for the fat content (%) where the highest fat content (9.72 +/- 0.25) was recorded for the fresh samples and the least value was recorded for those stored for sixty days. Ash content (%) and moisture content (%) do not show any significant change during storage. Mineral composition (Fe, Ca, Mg, P and Zn in mg/100g) and iodine content (microg/100g) of the samples showed a slight change with respect to duration of storage. pH values ranges between 5.20-6.90 while the total coliform count range was between 3.0 x 10(3)-7.5 x 10(6) with increasing values, as the duration of storage increases. Sensory evaluation of the fish samples on storage revealed that quality of the fish samples with respect to taste decreases with increasing duration of storage with the best quality (texture, odor and color) when freshly prepared; and that better quality during storage is obtainable during the first ten days of storage. These, by implication simply mean that fish should be stored for a short period of time to retain the taste, and provide both the protein and fat at optimal level.

Viral hemorrhagic fever antibodies in Nigerian populations.

Using the immunofluorescence test, a serosurvey for antibodies to five viral agents associated with hemorrhagic febrile infections was conducted with 1,677 human sera from different parts of Nigeria. Three hundred fifty-seven (21.3%) were positive for Lassa virus antibody, while antibodies to Rift Valley fever virus were detected in 42 (2.5%) of the sera. Testing for Rift Valley fever virus antibody was confirmed by plaque reduction neutralization test. Antibodies to Ebola and Marburg viruses were detected in 30 and 29 sera, respectively. Of the 357 Lassa virus antibody-positive sera, 297 (83.2%) were positive for Lassa only. In contrast, sera positive for Marburg were positive in combination with Lassa, Ebola, or Rift Valley fever viruses. Antibodies to Lassa and Rift Valley fever viruses were found in all locations in Nigeria, whereas Ebola and Marburg antibodies were found mainly in the northern savanna zones of Benue and Gongola, but not in the rain forest area of Ondo.

Yellow fever vaccination and pregnancy: a four-year prospective study.

During an outbreak of yellow fever (YF) in Nigeria in 1986-1987, women at various stages of pregnancy were vaccinated against YF, either because those pregnancies were not known at the time or because they requested vaccination out of fear of acquiring the disease. This offered an opportunity to assess the safety and efficacy of YF vaccine in pregnant women and the effect of this vaccine on their newborn children. Pre-vaccination and post-vaccination serum samples from the vaccinated pregnant women were tested by enzyme-linked immunosorbent assay and by neutralization tests for antibody to YF virus. The results showed that the antibody responses of these pregnant women were much lower than those of YF-vaccinated, non-pregnant women in a comparable control group. Follow-up of these women and their newborn children for 3-4 years showed no abnormal effect that could be attributed to the YF vaccine, which suggests that vaccination of pregnant women, particularly during a YF epidemic, may not be contraindicated.

Urban yellow fever epidemic in western Nigeria, 1987.

A large epidemic of urban yellow fever occurred in April and May 1987 in Oyo State, western Nigeria. The principal vector was Aedes aegypti, breeding in domestic water containers. The 1987 outbreak followed an epidemic of sylvatic yellow fever in eastern Nigeria the previous year, and probably resulted from introduction of the virus by viraemic travellers. The outbreak in Oyo State ended in early July, by which time 805 cases and 416 deaths had been officially notified. However, surveys of 3 villages in the epicentre, a region with over 4 million inhabitants, indicated an infection rate of approximately 20%, a clinical attack rate of 2.9% and a mortality rate of 0.6%, suggesting that the true incidence of cases and deaths far exceeded the official reports. Yellow fever virus was isolated from persons with fully developed yellow fever as well as mild febrile illness. One virus isolate was made from blood of an individual with mild illness, who had received 17D vaccine 5 d earlier; monoclonal antibody analysis showed that the isolate was a wild-type virus. Larval indices of Ae. aegypti were very high; however, low vector competence of the Ae aegypti population may have provided a constraint on spread of the epidemic. In late 1987 a third epidemic appeared in Niger State, northern Nigeria, with 644 reported cases and 149 deaths. The vector(s) involved is (are) unknown.

Expanded Programme on Immunization in Nigeria.

A brief description is given of the Expanded Programme on Immunization in Nigeria, which emphasizes the use of fixed facilities with outreach extension.