Helminth fauna of Oreochromis leucostictus (Pisces: Cichlidae) from a tropical lake, Lake Naivasha, Kenya

The helminth fauna of Oreochromis leucosticus (Trewavas) from Lake Naivasha is described. The study was carried out on 1,050 gillnetted fish caught over a period of 24 months at different sites within the lake. Oreochromis leucosticus which is a commercially important fish was observed to be a host of four helminth parasites. These were an acanthocephalan polyacanthorhynchus kenyensis (Schmidt and Canaris), a nematode contracaecum sp.. a trematode clinostomum sp. and a dilepidid cestode Amirthalingamia sp. Seasonal variation in prevalence, intensity of infection, organs infected and the variation in infection with the size, sex and body condition of the host are described. There was no seasonal variation in prevalence but intensity of infection was observed to increase with the age of the fish. Although male fish were observed to be more heavily infected, the parasites did not seem to have any significant effect on the body condition of the fish

Ecological studies of helminth parasites of the largemouth bass, Micropterus salmoides, from Lake Naivasha and the Oloidien Bay, Kenya

The parasites of 541 largemouth bass, Micropterus salmoides, were studied over a period of 12 months. The results showed that the bass from Lake Naivasha are paratenic hosts of Contracaecum sp. larva and final hosts for the acanthocephalan Polyacanthorhynchus kenyensis. The nematode occurred in large numbers in fish caught in the more saline Oloidien Bay but only in small numbers in those in the main lake. Bass in the main lake, however, were more heavily infected with acanthocephalans than those in Oloidien Bay. One of the major pathological effects of the acanthocephalan was perforation of the liver by the spiny proboscis. Seasonal variation was not apparent for either of the parasites. The intensity of infection by Contracaecum sp. larva increased with the size of the host and female fish were more heavily infected than males.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.German Academic Exchange Centre (DAAD) in Nairobi.mn201

Contamination of the minnow Rastrineobola argenta, through handling at landing sites and retail markets around Lake Victoria

Background: The quality of fish could be a challenge both locally and internationally as microbial contaminants may result in infections of humans when seafood is handled unhygienically. This is because enteric bacteria such as Escherichia coli, Staphylococcus aureus, Salmonella spp. and Vibrio cholerae are likely to  accumulate in fish where low hygienic standards are maintained. Therefore, studies on fish contamination are critical for the acceptance of fish food locally and in international markets.Objective: To evaluate and compare the microbiological quality of R. argentea at the fish landing sites and local retail markets in Homa Bay County.Design: Purposive, cross-sectional study.Setting: Fish landing sites and retail markets in Homa Bay CountySubject: Studies on fish contamination are critical for the acceptance of fish food locally and in international markets. In this study, Rastrineobola argentea were examined for microbial loads.Results: Samples indicated high levels of coliforms and Escherichia coli in fish. At the landing sites, coliforms ranged from 1.6 x 103 to 4.0 x 103 while E. coli was between 0.8 x101 and 4.8 x 102. In water samples, coliforms ranged between 1.3 x 103 and 1.8x106 / ml whereas E. coli was 1.1x102 to 4.6x101. Personnel hands were found to be contaminated with Salmonella typhimurium and Shigella  dysenteriae. The samples from markets had coliform and E. coli at 5.0x104 to 9.0x105 and 2.0x102 to 4.0x102 respectively.Conclusion: The findings demonstrate that precaution should be taken to improve the hygiene levels along the value chains to ensure that the quality of fish is not compromised

Ecological studies of parasites of commercially important fish species along the Kenyan Coast

WIOMSA/MARG-I/2002/01This study has been carried out over a period of four months (August, November 2001 and January, March 2002). The study aimed at establishing the magnitude of parasitization in different fish species as well as quantifying the relationship between the parasites and their fish hosts. Fish samples were collected from five main landing beaches: Vanga, Shimoni, Gazi, Mombasa and Kilifi. Fish samples examined for Parasites included: Siganus sutor, Plectorhynchus flavomaculatus, P. Sordidus, Lethrinus nebulosus, Sardinella gibosa, Scarus horrid, Sellar crumenophthalmus, Rastrelliger kanarguta, Parupeneus indicus, Mugil cephalus, Scombromorus commerson, Epinephelus macrospilas, Thunnus sp, Leptoscarus viagensis, L. sordidus and Hemiramphus far. Fish samples were purchased from fishermen who used a variety of fishing gears mainly gillnets, traps (madema), hand lines and cast nets. Results of this study have revealed that out of the 16 fish species examined, only 8 species were infected with parasites. These were the rabit fish (Siganus sutor), the mackerels (Selar crumenophthalmus, Scormbromorus commerson and Ratrelliger Kanarguta), Parrot Fish (Leptoscarus vagiensis,), the sardine (Sardinella gibosa), the tuna (Thunnus sp,), and the needle fish (Hemiramphus far). Of the eight species, S. sutor was the most heavily infected with helminth parasites while Sardinella and Leptoscarus were the main species infected with ectoparasites. Intensity of infection increased with age (size) especially in Siganus sutor where very young fish were rarely infected while adults were heavily infected (P<0.01).Publishe

Helminth fauna of Oreochromis leucostictus (Pisces: Cichlidae) from a tropical lake, Lake Naivasha, Kenya

The helminth fauna of Oreochromis leucosticus (Trewavas) from Lake Naivasha is described. The study was carried outon 1,050 gillnetted fish caught over a period of 24 months at different sites within the lake. Oreochromis leucosticuswhich is a commercially important fish was observed to be a host of four helminth parasites. These were anacanthocephalan polyacanthorhynchus kenyensis (Schmidt and Canaris), a nematode contracaecum sp.. a trematodeclinostomum sp. and a dilepidid cestode Amirthalingamia sp.Seasonal variation in prevalence, intensity of infection, organs infected and the variation in infection with the size, sex and body condition of the host are described. There was no seasonal variation in prevalence but intensity of infection was observed to increase with the age of the fish. Although male fish were observed to be more heavily infected, the parasites did not seem to have any significant effect on the body condition of the fish

Metazoan parasites of some commercially important fish along the Kenyan coast.

The parasitic fauna of some commercial fish species along the Kenyan coast was investigated at four localities between August 2001 and March 2002. The study was carried out to establish the extent of parasitisation of different fish species and quantify the relationship between the parasites and their fish hosts. Fish samples were collected once a month from four landing beaches. Sixteen fish species were examined out of which only eight were infested with ecto-and endo parasites. The infested fish species included: the rabbitfish (Siganus sutor), the mackerels (Selar crumenophthalmus, Scomberomorus commerson and Rastrelliger kanarguta), parrot fish (Leptoscarus vagiensis), sardine (Sardinella gibbosa), tuna (Thunnus sp.) and needle fish (Hemiramphus far). Of the eight species, Si. sutor was most infested with parasites while Sardinella and Leptoscarus were primarily infested wit h ectoparasites (isopods). Intensity of infestation increased with age (size), especially in Si. sutor, where very young fish had a low infestation rate, while adults were heavily infested (P 0.05).Publishe