Development and survival of Haemonchus contortus larvae on pasture at Vom, Plateau State, Nigeria.

The development and survival of the eggs of Haemonchus contortus on pasture at Vom were studied by depositing faecal pellets on grass plots over a period of 12 months. Development and survival to the infective larvae occurred throughout the study except during the dry season months of December to April. More infective larvae were recovered from the herbage in June, July and August than in other months. The survival time of the infective larvae ranged from 2 weeks in October to 10 weeks in June, July and August. Rainfall was the most important epizootiological factor influencing the development and survival of the infective larvae. Temperature was not a limiting factor.

Strongyloides papillosus: prenatal and transmammary infection in ewes.

The absence of larvae in lambs of six infected and controlled ewes immediately killed at birth without suckling may indicate the absence of prenatal infection. The ewes had larvae in their milk immediately prior to lambing and several hours afterwards. The persistence of infection, even after intestinal infection was removed with thiabendazole at 50 mg/kg body weigh, may be due to the pool of inhibited larvae. All the suckling lambs had patent infections within 4 to 5 days. Infection of suckling lambs with Strongyloides papillosus via milk from their ewes demonstrates the transmammary route of infection of this nematode.

A survey of gastrointestinal parasites in pigs of the Plateau and Rivers States, Nigeria.

Faecal samples were collected from a total of 1,000 pigs from the Port Harcourt and Jos areas of the Rivers and Plateau States, respectively, between January 1987 and March 1988. In the Jos area the parasite incidence was: Ascaris suum 53.1%, Trichuris suis 8.5%, Hyostrongylus rubidus 13.1%, Metastrongylus salmi 3.7%, Strongyloides ransomi 87.7%, Oesophagostomum dentatum 35.1% and Eimeria spp. 2.4% while in Port Harcourt the incidence rate was Ascaris suum 10.4%, Trichuris suis 47.2%, Oesophagostomum dentatum 50%, Hyostrongylus rubidus 2%, Ancylostoma duodenale 83.2% and Eimeria spp. 3.6%. The high rate of parasitic infections was due to poor management practices as shown by poor sanitary conditions. Access to human faeces, poor feeding and lack of deworming were also very evident. The different rates in the incidence of parasites in Jos and Port Harcourt areas were due to the varying moisture conditions in these states.

Observations on dry season strongyle infestations of permanent swamps grazed by cattle in Vom area, Plateau State, Nigeria.

Herbage samples were taken from 4 permanent swamps (2 heavily and 2 lightly pastured) located in Vom area every fortnight from November 1985-April 1986 and November 1986-April 1987. Larvae were extracted by washing and sedimentation and counts expressed as number of larvae per kg dry herbage. Worm larvae seen in faecal cultures were differentiated as Haemonchus, Cooperia and Oesophagostomum and these formed the bulk. Trichostrongylus, Bunostomum and Strongyloides were also seen but these were generally few. Lightly pastured permanent swamps were lightly infested and heavily pastured were contaminated with corresponding high infectivity. Heavily contaminated pastures are with risk from mild dry to late dry season. Dry season routine treatment is therefore necessary for cattle with access to swamps during the dry season especially heavily contaminated ones.

Strongyloides papillosus infestations of lambs in Plateau State of Nigeria.

The frequent appearance of patent infestations of Strongyloides papillosus in lambs under one week is observed, and it is suggested that either the short generation interval or pre-natal infection is the cause. Pathogenic effects associated with heavy infestations in young lambs consisted of anorexia, loss of weight, diarrhoea and a moderate anaemia. The lambs were usually very weak, unable to stand and laying prostrate. Death usually followed at this stage and three such lambs examined showed severe enteritis. There was also severe dermatitis noticed around the flanks and abdomen. The epidemiology studies which were based on worm egg counts taken at monthly intervals for a twelve-month period showed high counts in October and November, intermediate counts in May to August and low counts from February to April. The egg counts per g of faeces ranged from 100 to 18,000.