Wahab A. Rahman

An association of faecal egg counts and prolactin concentrations in sera of periparturient Angora goats

Faecal egg counts and serum prolactin concentrations in 13 pregnant and five non-pregnant Angora goats were monitored over a period of 20 weeks. The mean weekly egg counts of pregnant goats were significantly higher (P less than 0.01) than those of non-pregnant goats. In pregnant goats the mean egg counts in the 6 week post-partum period were significantly higher (P less than 0.01) than those of 6 weeks prepartum. The mean prolactin concentration of pregnant goats during the 6 week post-partum period was significantly higher (P less than 0.01) than that of 6 weeks pre-partum. During the 6 to 3 weeks before parturition, the prolactin values generally remained low (below 100 ng ml-1). The rise in prolactin concentration started between 3 weeks and 1 week before parturition. Only in pregnant goats was there a positive linear regression between prolactin levels and faecal egg counts.

The establishment and development of Haemonchus contortus in goats

Twelve goats were inoculated with 40,000 third-stage Haemonchus contortus larvae and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. More worms established in the fundic, than in the middle or pyloric thirds of the abomasum. Early development occurred within the mucosa; emergence into the lumen started between 7 and 11 days after infection. By 4 DAI, all worms had completed the third moult to the L4 stage. At 11 DAI the majority of the worms were adults. A mean of 13.2% of the female worms had eggs in their uteri at 18 DAI; by 21 DAI more than half of the female worms had eggs in their uteri. The development of H. contortus was essentially similar to that described in sheep.

Changes in liveweight gain and blood constituents in experimental infection of goats with a goat-derived compared with a sheep-derived strain of Haemonchus contortus

Two groups of goats were experimentally infected with two different strains of Haemonchus contortus and compared with the controls. Group A animals were infected with a goat-derived strain (GDS) while Group B animals were infected with a sheep-derived strain (SDS). Changes in the liveweights and some blood constitutents between the two infected groups were compared. The pathogenic effects of the GDS larvae were generally more serious when compared with those of the SDS larvae.

Seasonal variations in the numbers of trichostrongylid nematode eggs and their larvae in the faeces of farmed goats in Malaysia

Faecal worm egg counts of goats from two farms in Penang Island, West Malaysia, were monitored over a period of 14 months. The faecal egg count pattern followed that of total rainfall. The humid tropical environment was favourable for the development of various species of trichostrongylid nematodes, namely Haemonchus contortus, Trichostrongylus spp., Oesophagostomum spp. and Cooperia spp. Generally, H. contortus was observed to be the predominant species, more so in the monsoon months of the year.

An assessment of thiabendazole-resistant nematodes in some smallholder goat farms of Malaysia using the egg hatch assay method

Faecal samples were collected from 48 randomly selected smallholder goat farms in northern Peninsular Malaysia. The nematode eggs extracted were tested for resistance to thiabendazole using the egg hatch assay technique. Thiabendazole resistance was found on 19% of farms tested.

Changes in liveweight gain, blood constituents and worm egg output in goats artificially infected with a sheep-derived strain of Haemonchus contortus.

Two groups of goats were dosed with 10,000 and 20,000 sheep-derived strain (SDS) larvae of Haemonchus contortus respectively. Over a period of 42 days goats dosed with 20,000 larvae lost more weight than those dosed with 10,000 larvae. Infected goats showed anaemia from about 2 weeks after infection as well as reduced levels of total serum proteins and albumins.

In vitro activity of neem (Azadirachta indica) and cassava (Manihot esculenta) on three pre-parasitic stages of susceptible and resistant strains of Teladorsagia (Ostertagia) circumcincta

Anthelmintic resistance of gastrointestinal nematodes is considered as one of the main limiting factors causing significant economic losses to the small ruminant industry. The anthelmintic properties of some plants are among the suggested alternative solutions to control these parasitic worms. The present study investigated the anthelmintic activity of neem (Azadirachta indica) and cassava (Manihot esculenta) leaf extracts against the susceptible and resistant strains of one of the most important nematodes in small ruminants, Teladorsagia (Ostertagia) circumcincta. Three different in vitro tests: egg hatch test, larval development assay, and larval paralysis assay were used to determine the efficiency of neem and cassava extracts on three pre-parasitic stages of T. circumcincta. The LC(50) was determined for the most potent extract in each plant as well as the phytochemical tests, total tannin quantification and cytotoxicity on peripheral blood mononuclear cells of goats. The results revealed a high anthelmintic activity of neem methanol extract (NME) and cassava methanol extract (CME) on both strains of T. circumcincta without significant differences between the strains. The first stage larvae were more sensitive with the lowest LC(50) at 7.15 mg/ml and 10.72 mg/ml for NME and CME, respectively, compared with 44.20mg/ml and 56.68 mg/ml on eggs and 24.91 mg/ml and 71.96 mg/ml on infective stage larvae.

The prevalence of Plasmodium falciparum and P. vivax in relation to Anopheles maculatus densities in a Malaysian village

Blood from most of the residents of a remote village in northern peninsular Malaysia, bordering Thailand, was examined for malaria parasites monthly for 1 year. Plasmodium vivax was the commonest infection, but P. falciparum and mixed infections also occurred. Monthly collections of the malaria vector, Anopheles maculatus showed a positive correlation between mosquito densities and malaria positivity in the human population and a negative correlation with rainfall.

Infection of goats with Haemonchus contortus and Trichostrongylus colubriformis: histopathology and pH changes.

Two groups of goats were experimentally infected with Haemonchus contortus and Trichostrongylus colubriformis, and killed at various days after infection (DAI). The percentage of worms that established in the abomasum and the small intestine was low. At necropsy, abomasums from infected goats had thickened walls and oedematous folds. At 7 DAI there was an initial infiltration of eosinophils and some neutrophils which tend to increase with age of infection. The mean pH of the abomasum in goats infected with H. contortus was 5.43 (range 5.3-5.7), while that of the control goats was 3.30 (range 2.8-3.7).

The establishment and development of Trichostrongylus colubriformis in goats.

Twelve goats were inoculated with 20,000 infective larvae of Trichostrongylus colubriformis and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. Most of the worms established within the first 3 m of the small intestine. There was little relocation or loss of nematodes after establishment. The worms started to migrate from the mucosa to the lumen 11 days after infection. At 4 DAI, 63% of the worms were still at the late L3 stage; the remainder of the worm population had completed the third moult to the L4 stage. The population at 11 DAI comprised largely young adults. When 21 DAI was reached, about 57% of the female worms had eggs in their uteri.