AN APPRAISAL OF RABIES OCCURRENCE AND CONTROL IN KISUMU MUNICIPALITY, KENYA.

BACKGROUND: Rabies is a serious neglected disease which occurs worldwide. In urban areas, the control of the diseaseis expected to be hampered by several unique constraints. OBJECTIVE: To appraise the occurrence and control of rabies. STUDY DESIGN: The tools used in the study included key informant interviews with senior veterinary and medical officers and a questionnaire survey on 15 veterinary officers and 9 human physicians. The occurrence of animal bites and costs involved in treatment was also investigated using retrospective hospital data for the year 2007. SETTING: Kisumu Municipality, Kenya. RESULTS: The control of rabies was under the Veterinary Department through dog vaccinations and baiting, and also under the Department of Public Health (DPH) through people vaccinations and post exposure treatments. The constraints observed were poor coordination in rabies control efforts, understaffing and limited resources. Animal bites were common with 1270 cases reported during 2007. The post-bite rabies vaccines were mainly purchased from local chemists at KES 7,500 per full dose. This amounted to an annual total cost of KES 9,525,000 (136,071 USD). The bites were mainly from domestic dogs (89%) and occurred commonly in highly populated areas. The mean age of people with bites was 21 (2.5 - 78) years, showing that young people had a higher risk. Males (59%) were at higher risk of bites than females (41%). CONCLUSIONS: It would be important for the relevant departments to harmonise their rabies control strategies and also address the prevalent constraints by using local networks. The incidence of rabies and the associated epidemiology needs proper updated documentation with a view of carrying out mass vaccination of dogs at times free of cost to the economically disadvantaged owners.

Seroprevalence of Cysticercus cellulosae and associated risk factors in free-range pigs in Kenya.

Porcine cysticercosis is an emerging zoonosis with public health and economic importance. A cross-sectional study was undertaken to investigate the disease in free-range pigs on 182 smallholder farms in Busia District, Kenya. The survey households were selected using a snowballing technique. Serum samples were obtained from 284 pigs of all ages at farm level and 37 pigs from slaughter slabs in the study area. The samples were analysed for the presence of cysticercus antigen using an antigen enzyme-linked immunosorbent assay (ELISA). A structured questionnaire was administered to determine the risk factors for porcine cysticercosis on the study farms. At pig level, the total number of pigs testing positive were 11, resulting in a seroprevalence of 4% (95% confidence interval (CI): 1.9-6.2%), while the farms with a positive pig were 9% (95% CI: 3.9-14.1%). All pigs examined in the slaughter slab survey were seronegative. The distribution of possible risk factors for porcine cysticercosis that were observed at farm level was as follows: free-range pig keeping (100%), history of human taeniosis infection in a family (51%), slaughtering of pigs at home (20%), lack of meat inspection (15%) and absence of latrines (15%). The only significant (χ2 = 4.4, P = 0.034, odds ratio (OR) = 3.8) risk factor associated with the occurrence of cysticercosis was lack of latrines at household level. The study shows that porcine cysticercosis is prevalent in free-range pigs in Busia District, Kenya and thus control measures need to be instituted.

Questionnaire survey on urban and peri-urban livestock farming practices and disease control in Kisumu municipality, Kenya.

To characterise the urban livestock keeping practices and constraints in Kisumu municipality, Kenya, a questionnaire survey was carried out. Thirty-four contact farmers were interviewed on general farm characteristics and production constraints. The farming activities were categorised as either livestock only (41%), or mixed crops and livestock (59%). The surveyed farmers kept mainly cattle (100%), chickens (82%) and goats (74%). Most (94%) of the farmers had kept livestock for prolonged periods mainly for income generation (97%) and domestic consumption (59%). These data show that livestock keeping was popular and could be harnessed to increase food security, although the farmers kept mainly low-producing indigenous cattle (98%) which were grazed on unutilised land. The main production constraints mentioned by farmers included diseases (100%), poor fertility (68%) and lack of feed (56%). The diseases varied with species of ruminants and included lumpy skin disease (71%), diarrhoea (65%) and helminthosis (62%). The source of advice on management and treatment of the livestock was almost equally from private and government veterinary personnel. To improve livestock productivity, it is recommended that key stakeholders address the constraints mentioned in this study and in particular that the occurrence of diseases should be investigated with a view to developing sustainable control strategies.

Occurrence of risk factors for zoonoses in Kisumu City, Kenya: a questionnaire survey.

OBJECTIVE: To determine the occurrence of risk factors amongst farmers keeping livestock in Kisumu municipality, Kenya. METHODS: Thirty four contact house-holds involved in livestock keeping constituted the study group. The head of the household was interviewed using a structured questionnaire relating to public health issues affecting water, food and sanitation RESULTS: The water consumed at the household level originated from the taps (56%), bore holes (18%), local rivers (15%) and wells (15%). The wells were shallow and open to contamination. Fourty one percent (41%) of the households consumed water without boiling or any other form of treatment. Farmers had a history of slaughtering cattle (79%) and pigs (66%) at their homes and these animals were not inspected by legalized government officers. During the last five years, porcine cysticercosis and taeniosis (9%) were reported to occur amongst the homesteads. Although toilets were found in most homes, some were overflowing (27%), while children below 4 years (mean) of age defaecated in the bushes/grass within the neighbourhood. Most farmers (62%) disposed the manure next to the animal boma resulting in creation of small manure 'hills' that were a nuisance and breeding ground for vector flies. Other risk factors for disease transmission included consumption of unwashed raw food (48%), dried raw fish (21%) and failure to wash cows' udder before milking (29%). CONCLUSION: The study shows that risk factors for transmission of zoonoses are common in house holds keeping livestock in the study area and highlights the need for public health education to raise awareness of these factors. Further studies should be conducted to determine the possibilities of zoonoses occurrences among the human population.

The effects of anthelmintic treatments against gastrointestinal nematodes on the performance of breeding ewes and lambs on pasture in semi-arid Kenya.

The effects of anthelmintics treatments in controlling gastrointestinal nematodes in breeding ewes in a semi-arid area of Kenya were determined. The study carried out during two breeding seasons, between June 2000 and December 2001 where albendazole was administered to groups of ewes, 2 weeks before mating, 3 weeks to lambing and mid lactation indicated significantly lower nematode egg counts in treated than untreated groups of ewes. In the first breeding season, reduced rainfall resulted in pasture scarcity and weight loss in both groups of ewes through out the gestation period, but losses were higher for the untreated group. In the second season, both groups of ewes showed a steady increase in weight gain during the gestation period and post-partum, but weight gains were higher in the treated group. In lambs, weight gains at 6 weeks were higher for treated ewes than control groups, in both breeding seasons. The results of this trial indicate that anthelmintic treatments in breeding ewes in the study area are beneficial in reducing gastrointestinal nematode infections and improving performance of the ewes and their lambs. In addition to the treatments, breeding ewes should be given feed supplementation particularly during periods of pasture scarcity.

The effect of weather on the occurrence and magnitude of periparturient rise in trichostronglyid nematode egg output in Dorper ewes in a semi-arid area of Kajiado District of Kenya.

An investigation was carried out to assess the effects of weather on the occurrence and magnitude of the periparturient rise (PPR) in trichostrongylid nematode egg output in breeding Dorper ewes. The study was conducted over three breeding seasons on a ranch in the semi-arid area of Kajiado District in Kenya between June 1999 and December 2001. During each breeding season 20 ewes randomly selected from the breeding stock and 20 others selected from the unmated yearlings were monitored for faecal strongyle egg counts every 3 weeks. The lambing seasons were timed to coincide with the onset of the short rains (October-November 1999), the mid-short rains (November-December 2000) and the end of the dry season (September-October 2001). In each season higher egg outputs were recorded in the peri-parturient ewes compared to the unmated yearlings. The highest PPR occurred in September 2001, when lambing coincided with the end of the dry season, possibly as a result of maturation of hypobiotic larvae. The lowest PPR occurred in November 2000 when the onset of lambing coincided with the mid-short rains, possibly owing to low pasture infectivity associated with a long dry spell between January and October of the same year. The results of this study indicate that PPR occurred when lambing coincided with both the wet and the dry seasons. However, the magnitude was greatly influenced by the season when lambing occurred. It was also influenced by resumption of development of hypobiotic larvae and the nutritional status of the ewes. Not only should control of gastrointestinal nematode parasites in this area aim at preventing the occurrence of PPR by treating ewes 2-3 weeks before they are to lamb and during lactation, but the anthelmintic used must also eliminate hypobiotic larvae. In addition, the animals must be given supplementary feeding during this period.

Epidemiology of gastrointestinal helminths infections in Dorper sheep in a semi-arid area of Kenya.

A survey on the prevalence and intensity of infection with gastrointestinal helminths of Dorper sheep in relation to age and weather factors was carried out on a ranch in Kajiado district, a semi-arid area of Kenya for a period of 13 months (May 1999 to May 2000). Faecal samples from lambs (3 months to 1 year), yearlings (1-2 years) and adult breeding ewes (2-4 years) were examined for helminth egg output and helminth genus composition at 3-week intervals. The results indicated that the prevalence of strongyle and tapeworms infections were highest for lambs, followed by the adult breeding ewes and then for the yearlings. In all age groups the proportions of infected animals were higher during the wet season than in the dry season for both nematodes and tapeworms. The mean strongyle egg counts were higher during the dry season for lambs, but were higher during the wet season for the other age groups. Mixed strongyle infections were detected, with Trichostrongylus (55 %), Haemonchus (28 %), Cooperia (10.5 %) and Oesophagostomum (6.5 %) being the most frequently encountered genera throughout the study period. The trends in strongyle faecal egg counts indicated the occurrence of hypobiosis, with resumption of development towards the end of the dry season and at the onset of the short rains in October and November. Self-cure was also observed in September and November in all age groups, although less frequently in lactating ewes. The prevalence and intensities of infection with gastrointestinal helminths in this area appeared to be influenced by the age of the host and weather factors.

Occurrence of peri-parturient rise in trichostrongylid nematode egg output in Dorper ewes in a semi-arid area of Kajiado District of Kenya.

An investigation on the occurrence of peri-parturient rise in trichostrongylid nematode egg output in breeding ewes was carried out on a Ranch in the semi-arid area of Kajiado District in Kenya during the period May 1999-April 2000. During the study, 20 ewes randomly selected from the breeding stock and 20 un-mated female yearlings were monitored for faecal strongyle egg output every 3 weeks. A significant peri-parturient rise in faecal egg output occurred at around the time of lambing and throughout the lactation period in the mated ewes, but not in the un-mated yearlings. The occurrence of peri-parturient rise in breeding ewes towards the end of the dry season and at the onset of the short rains was enhanced by the resumption of development of hypobiotic larvae. Self-cure occurred in the un-mated yearlings in September 1999 during the dry season and in November-December 1999 during the wet season, but was less obvious in the pregnant and lactating ewes. The peri-parturient ewes contributed to higher pasture contamination at a time when highly susceptible lambs were grazing alongside. Therefore, the control of gastrointestinal nematode parasites in ewes in this area should aim at reducing the effects of this phenomenon through treatment of ewes about 2-3 weeks to lambing and during lactation.

Development, survival and availability of gastrointestinal nematodes of sheep on pastures in a semi-arid area of Kajiado District of Kenya.

A study was carried out on a ranch in the semi-arid area of Kajiado District in Kenya during the period July 2000 to June 2001 to determine the seasonal patterns of development and survival of gastrointestinal nematodes of sheep on pastures. A series of plots were contaminated with sheep faeces every month and pasture samples were collected weekly for the recovery and identification of larvae. The availability of infective larvae on naturally contaminated pastures was also monitored on the paddocks grazed by sheep and around the night pen and the watering point every month from July 2000 to June 2001. The results from the examination of the pasture samples indicated that rainfall distribution was the major factor governing the development and survival of the pre-parasitic stages. No parasitic larvae were detected from the plots contaminated during the dry months from July to October 2000, but development and translocation of infective larvae on pastures occurred on plots contaminated during the rainy seasons and soon after when relatively high moisture was present in the herbage (November 2000 to June 2001). During this period, peak larval counts occurred between the first and the second week post contamination, then declined to undetectable levels between week 4 and 16 post contamination. The lack of development of infective larvae during the dry season and the relatively rapid decline of their population during the wet season presents an opportunity for the use of pasture spelling as a means of helminth control in the study area. The availability of infective larvae on naturally contaminated pastures, around the night pen and around the watering point also followed the rainfall distribution pattern. Infective larvae were consistently recovered around the watering point throughout the study period. This indicated that the point is an important source of infection for sheep, especially during the dry season when other pastures are non-infective.

Characterisation of Theileria parva isolates from Kiambu district, Kenya.

Four Theileria parva isolates from Muguga area of Kiambu district, Kenya, were used to establish schizont-infected cell lines. Their protein antigens were then separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS page). The isolates were subsequently subjected to protein analysis and characterisation by the western immunoblotting technique. Probing for the polymorphic immunodominant molecule (PIM) was done using monoclonal antibody no. 4. SDS page detected up to 20 protein antigens of molecular mass 35,000-180,000 Da. The western blot analysis revealed a greater heterogeneity in the molecular mass (M(r)) of PIM than previously thought. The M(r) of PIM varied between 80 and 90 kDa. The isolates further revealed different densities of surface epitopes with variable reaction to the monoclonal antibody. The implications of these findings to the epidemiology of east coast fever and immunisation programmes are discussed.

The role of parasitic diseases as causes of mortality in cattle in a high potential area of central Kenya: a quantitative analysis.

Postmortem records of cattle brought to the Veterinary School in Kabete near Nairobi were examined for a period of 15 years (1984-1998, inclusive) in order to establish the role that parasitic diseases played as causes of death. The cattle were mainly of exotic breeds but a few were crosses or of indigenous breeds. There was a total of 1413 cases of deaths from various diseases of which 177 (13%) were due to parasites. The tick-borne diseases were in high proportions and accounted for 84,7% among the parasitic causes, which represented 10,6% of all the deaths recorded. The main tick-borne disease was East Coast fever (ECF) (65%) followed by heartwater (10,2%), babesiosis (5,1%) and anaplasmosis (4,5%). Hydatidosis was responsible for 7,3% of deaths from parasitic causes. Deaths from ECF were recorded in all the 15 years and in high proportions compared to those due to heartwater (8/15), babesiosis (7/15) and anaplasmosis 5/15). Over the period under consideration, no decline was noted among various disease conditions despite advances made in controlling tick vectors and in the treatment of various parasitic conditions. The area covered by this study has the advantage of having several veterinary-related institutions close by. Hence knowledge and awareness about livestock diseases is relatively high compared to other parts of the country. It is therefore challenging to the Veterinary Department to examine the service delivery systems and other factors that may contribute to the persistent presence of these fatal parasitic conditions of cattle.

Comparative parasitological and haematological changes in two breeds of sheep infected with Fasciola gigantica.

Twelve each of Red Masai and Dorper sheep, aged between 6 and 9 months, were acquired from a Fasciola-free area of eastern Kenya. Each breed was divided into two groups of 6. The sheep in one group of each breed were experimentally infected with 400 viable metacercariae of Fasciola gigantica. The other group of 6 sheep of each breed remained as uninfected controls. The animals were monitored regularly for any evidence of disease. Blood samples taken weekly revealed a general reduction in red cell counts and packed cell volume, which was much faster in the infected Dorper sheep than in the Red Masai. This reduction started from the tenth week after infection and persisted to the end of the experiment 18 weeks post infection (PI). The absolute eosinophil counts rose in all the infected animals, but the values were higher among the Dorper than among the Red Masai. Patency occurred at weeks 12 and 13 PI in the Red Masai and Dorpers, respectively, with the latter shedding significantly more fluke eggs. The worm recovery rates were higher among the Dorpers than among the Red Masai, though not significantly so. On the basis of egg counts and clinicopathology, the Dorper sheep were considered to be more susceptible to F. gigantica infections.

A comparison of serum biochemical changes in two breeds of sheep (Red Masai and Dorper) experimentally infected with Fasciola gigantica.

Twelve Red Masai and 12 Dorper sheep aged between 6 and 9 months, were acquired from a fluke-free area and sheep of each breed divided into two equal groups of six. Each animal in one group of each breed was experimentally infected with 400 viable metacercariae of Fasciola gigantica. The other groups acted as uninfected controls. Blood samples were taken at weekly intervals for the determination of serum bilirubin, albumin, and gamma glutamyl transferase levels. Following the establishment of infection, albumin levels declined in both breeds of infected animals without any significant difference between the two breeds. However, serum bilirubin and gamma glutamyl transferase (GGT) in the infected animals were elevated significantly more in the Dorper than in the Red Masai sheep. Based on these findings, it would appear that Dorper sheep are more susceptible to the infection than Red Masai sheep.

Isolation of Besnoitia wallacei in Kenya.

The development of Besnoitia wallacei was studied in 13 cats fed on tissues of mice and rats previously infected with B. wallacei. The cats were serially killed between Day 1 and Day 16 of infection, and histological sections from the liver and intestines were examined. Asexual stages were seen in both the small intestines and the liver between Day 6 and Day 16 post-infection. Mature microschizonts in intestinal epithelial cells measured 22.6 microns x 14.7 microns (n = 15). Macroschizonts in intestinal lamina propria measured 66.6 microns x 50.3 microns (n = 25). Those in the liver measured 70.9 microns x 55.0 microns (n = 5). Sexual stages were seen in epithelial cells of the small intestines only.

Immunohistological demonstration of antigenicity of the various endogenous stages of Eimeria apsheronica in goats.

Ten naive goat kids obtained soon after birth were reared coccidia-free in cages indoors. At one month of age they were each infected with 25,000 oocysts of E. apsheronica. Infection was monitored by examining the faeces for oocysts for two and a half weeks after patency. They were then euthanized and sections of their small intestines showing gross coccidal lesions were fixed for histology. Intestinal sections were incubated in pre-infection and post-infection sera to detect any antigen-antibody reactions using diaminobenzidine (DAB) as the stain. The sections treated with pre-infection sera stained very poorly in comparison to those treated with post-infection sera. The conclusion is drawn that serum antibodies which developed after infection reacted with the endogenous stages of the parasite and were histologically demonstrable.

The relationship between coccidial and helminth infections in sheep and goats in Kenya.

Studies on prevalence of coccidian oocysts and their infection levels (oocysts g-1, OPG) were carried out among various age groups of sheep and goats from different geographical locations in Kenya. Prevalent species of Eimeria were identified and levels of infection with strongyle eggs (eggs g-1, EPG) examined. A significant difference was found in the EPG levels between various farms but not in the OPG levels; this was attributed to the relative susceptibility of various preparasitic stages of helminths to adverse climatic conditions, especially desiccation, compared with coccidian oocysts. There was a negative correlation between OPG levels and the age of animals as a result of acquired immunity. Between OPG and EPG values there was a positive correlation which is in tandem with the role of contamination in the acquisition of both types of infection. Sheep were found to shed significantly more oocysts and helminth eggs than goats; this could be related to the differences in their mode of feeding, i.e. grazing and browsing respectively. Young age (under 1 year) and confinement were found to contribute to high prevalence of oocysts in faecal samples. In sheep, a total of ten species of Eimeria were identified, the most prevalent being E. ovina (43%) and E. ovinoidalis (16.5%). In goat samples, eight species were identified, the commonest being E. arloingi (37.5%) and E. ninakohlyakimovae (35.2%).

Eimeria apsheronica in the goat: endogenous development and host cellular response.

Most first generation schizonts of Eimeria apsheronica developed in the jejunum; others were distributed throughout the small intestine and occasionally in the caecum. Some were also found in the mesenteric lymph nodes, which were oedematous and haemorrhagic. In the intestine, haemorrhage and congestion were seen before parasites were detected, and continued throughout all later stages. Schizonts occurred in the lamina propria and occasionally in the submucosa, where they sometimes caused a cellular inflammatory response. Schizonts were first seen at 8 days post-infection (DPI); they had poorly defined nuclei and were enclosed in a capsule-like wall. At 16 DPI, many had matured, had a mean size of 125 x 82 microns, and were filled with numerous spindle-shaped merozoites, which were in ranks and loops. At 18 and 20 DPI, when small white lesions (1-3 mm in diameter) were observed in the jejunum and elsewhere in the small intestine, a second generation of schizonts, macrogametes, microgametocytes and maturing oocysts were seen, in the epithelial cells of the small intestine and caecum. Their mean sizes, respectively, were: 26.2 x 18.9, 24.7 x 18.5, 30.2 x 21.7 and 26.6 x 19.3 microns. Macrogametes contained basophilic central and eosinophilic peripheral granules. The sexual stages were associated with a generalized cellular inflammatory response.

Experimental infections with coccidiosis and serum antibody quantitation in two breeds of goats.

Two goat breeds, Anglonubian and Saanen were obtained at an early age and reared coccidia-free until they were 1 month old. They were then infected with 200,000 sporulated oocysts comprising mainly Eimeria christenseni (49%), E. apsheronica (29%) and lesser proportions of E. arloingi, E. hirci, E. ninakohlyakimovae and E. alijevi. Following patency, the number of faecal oocysts per gram were determined for each animal and body weights taken weekly. An ELISA was developed to assay antibody titres in pre- and post-infection sera of each individual kid. Cleaned unsporulated oocysts were sonified and the resulting soluble antigen used. Anglonubians shed significantly more oocysts daily (P less than 0.01) and also suffered greater retardation in growth. Initially both breeds had very similar growth rates, however post-infection weekly body weight gain among the Anglonubians was on average 1100 g compared to 1300 g for the Saanens. Antibody titres post-infection increased significantly among the Saanens (P less than 0.01) and also all but one among the Anglonubians recorded an increase in antibody titres. Unsuckled kid serum was devoid of any antibody activity.