| dc.description.abstract | This study was conducted in three phases. Phase one aimed at studying the prevalence and significance of coccidiosis in Kenyan goats from selected areas. The various species of Eimeria were also identified.
Faecal samples were obtained per rectum from goats in various selected areas of Central province, Eastern province and Rift Valley province.
These samples were analysed in the laborotary at Kabete Campus to give the oocysts per gram of faeces (OPG) and cultured in 2.5% Potassium dichromate for sporulation. Identification of the various species was done by morphological characteristics of the sporulated and unsporulated oocysts. These included colour, shape, sizes, and presence or absence of micropylar cap. These were compared with standard micrographs from Norton (1986) and O'Callaghan (1989).
The following species were identified Eimeria arloingi, E. hirci., E. ninakohlyakimovae, E. alijevi, E. christenseni, E. jolchijevi. E. caprovina, E. caprina and E. apsheronica. E. jarloincri was most prevalent while E. caprina was the least prevalent.
The overall prevalence of the individual species were E. arloingi 37.67%, E. ninakohlyakimovae 24.44%, E. hirci 17.21%,E. g-1 iievi 10.18%, E. christenseni 5.56%, E. caprovina 3.57%, E. jolchi-jevi 1.05%, E. apsheronica 0.21% and E. caprina 0.11%.
These percentages were obtained from the average proportion °f oocysts of each species encountered and measured from 360 samples.
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In terms of proportion of oocysts encountered E. arloingi ^ had the highest percentage oocysts while E. caprina had the
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least. This study showed that Kenyan goats from the selected areas do harbour and shed coccidial oocysts and coccidiosis is preva1ent.
Phase two of the study was aimed at studying the seasonal and age variation of mean oocysts per gram (OPG) and various species of Eimeria in Ngong Veterinary Farm and Kitengela over a period of three months.
Weekly samples were obtained from ten kids and ten adults from each farm. These samples were laboratory analysed to give the mean oocysts per gram and various species of Eimeria present in each sample identified. This data was then analysed statistically to give the variations due to season and age on the mean oocysts per gram (OPG) and the species of Eimeria.
Analysis of variance (ANOVA) tables were drawn from least square computer mean values to give the significance of the variations. Where p<0.01 it was considered highly significant while p<0.05 it was considered significant.
There was a highly significant variation in the mean OPG over the study period. The values were high for weeks with heavy rainfall and weeks that followed the rainy weeks and low for dry weeks.
There was also a highly significant variation in proportion °f the individual Eimeria species in the total count. Eimeria arjj3_inc[i. had the highest square mean value of 52.06 + 1.29 while E* ~jo 1 ievi had the lowest value of 0.50 + 1.31. E. hirci was the second highest with a value of 17.38. The others were E. ninakohlyakimovae 13.67, E. ali j evi 12.63, E. christenseni 2.98, E. caprovina 0.77. E. apsheronica and E. caprina were not encountered in this study. This showed that E. arlolngi was the most prevalent and common species encountered over the study period and E. jolchijevi the least.
The number of oocysts counted for each individual species was also highly significant. The highest number of oocysts counted per species were E. arloingi while E. jolchijevi oocysts were the lowest. E. alijevi were the second highest. The least square mean values were E. arloingi 50.45, E. alijevi 26.10, E. hirci 19.75, E. ninakohlyakimovae 14.84, E. christenseni 5.57, E. caprovinh 2.12 and E. jolchijevi 0.9 per sample. E. ar1oingi was the most abundant species followed by E. alijevi while E. jolchijevi was the least abundant.
There was no significant variation in the levels of OPG shed by the various species of Eimeria and between different ages of the goats. The values were the same for kids (3-6 months) and adults (21-24 months) in both farms.
Between the two farms, the mean oocysts per gram (OPG) was highly significant. Ngong Veterinary farm had the highest mean value of 6850.50 while Kitengela had mean value of 1516.32. This showed that goats at Ngong were shedding more coccidia oocysts than those at Kitengela.
The number of oocysts per species counted for each farm was also highly significant. Ngong had the highest number of oocysts per species with a least square mean value of 22.18 while Kitengela had a mean value of 11.51 per species. There was a higher number of oocysts per species at Ngong than at Kitengela. The proportion of parasite were the same for both farms in kids and adults with no significant variation.
Phase three of the study aimed at studying the pathology of natural infections.
Six kids aged between one and four weeks with naturally acquired infections were used. The species of Eimeria infecting these kids were identified as E. ar1oingi 45% (most prevalent), E. ninakohlyakimovae 15%, E. hirci 15%, E. alijevi 10%, E.
caprovina 3% while E. jolchijevi, E. caprina and E.
apsheronica composed 2%. 360 oocysts were observed from a
pooled sample. The lesions in the intestinal tract were noted by type, size, location and distribution.
The macroscopic lesions were restricted to the small
intestines. They were more marked in the jejunum.
The serosal surface was congested in all the kids while mucosal hemorrhages were observed in one kid in the jejunum and ileum.
Greyish-white nodular lesions were observed in two kids. In one kid they were multiple and distributed from the duodenum upto the ileum. They were more numerous in the jejunum where they appeared to fuse together measuring between l-5mm in diameter. These were not visible from the serosal surface.
In the second kid the lesion was solitary measuring 1mm in diameter in the jejunum and visible from the serosal surface Microscopic lesions were found throughout the small intestines, caecum and colon but were more severe in the small intestines. There was mild subacute enteritis, congestion and oedema of the submucosa but were more severe in the small
intestines.
The glandular epithelial cells were hypertrophied and some had macrogametes, microgametes and developing oocysts.
The macrogametes were of various sizes in all the
sections. The developing oocysts were also of varying sizes in these sections and were distributed from the duodenum upto the colon.
Villi erosion was particularly marked in the distal
jejunum and ileum while fusion occurred in the duodenum and proximal' jejunum.
The main cellular reaction was mononuclear cell infiltration involving mainly lymphocytes, few plasma cells, macrophages and some eosinophils.
The greyish-white nodular lesions were hypertrophied glandular epithelial cells, fused villi, macrogametes, microgametes, developing and mature oocysts. | |
