P.W.N. Kanyari

Characteristics of the smallholder free-range pig production system in western Kenya

Free-range pig farming is common amongst the small-scale farmers in western Kenya. In order to determine the characteristics of this type of production system, a cross-sectional questionnaire survey on farm characteristics and management was collected from 182 farmers in Busia District. The mean farm size was one acre, while the mean number of pigs per farm was 3.6. Pigs were mainly kept as a source of income (98%) and majority were of cross breed variety (64%). The production systems included farrow to weaner (12%), porker to finisher (36%), and mixed (46%). Sixty five percent (65%) of the pigs were tethered and housing was not provided in 61% of the farms. Most of the feeds were sourced locally. Lack of castration and delayed weaning of pigs was observed on 49% and 30% of the farms, respectively. The main production constraints included pig diseases (81%) and high cost or lack of feed (81%). Haematopinus suis infestations and worm infections were considered to be the most important diseases by 71% and 55% of the farmers, respectively. Farmers had moderate knowledge on parasitic disease diagnosis with 31% and 62% not having a history of either deworming or spraying pigs with acaricides, respectively. Marketing constraints were common amongst the farmers and included poor prices and inadequate market information. In conclusion, the production system was characterized as low-input with an income objective. Future research and development approaches should focus on the integration of free-range farmers into the country’s market chains through access to extension services.

The relationship between coccidal 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%).

Development, Survival and Availability of Gastrointestinal Nematodes of Sheep and 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.

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.

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.

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.

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.

Molecular detection of Anaplasma platys infection in free-roaming dogs and ticks from Kenya and Ivory Coast

BackgroundAnaplasma platys is a bacterium parasitic in the canine platelets, representing the causative agent of canine cyclic thrombocytopenia, with a worldwide distribution, mainly in tropical countries. The agent has zoonotic potential, being reported in several human clinical cases. The suspected vector is the tick Rhipicephalus sanguineus (sensu lato), widely distributed in animals and humans in the tropical regions of South America, Africa, Asia and Australia, but also in southern Europe. Only few scattered data concerning the epidemiology of A. platys in sub-Saharan Africa are available. The aim of our study was to evaluate the epidemiological status of A. platys in dogs and cats from rural communities in eastern and western Africa, where dogs and their ticks live in close contact with humans.MethodsA total of 216 canine and 22 feline blood samples and ticks feeding on them were collected in 2013 and 2014 from eight localities in Ivory Coast and four localities in Kenya. PCR was performed using specific primers targeting a portion of the 16S rRNA gene, followed by sequencing.ResultsThe main results highlight the high prevalence of A. platys infection in dogs in both Eastern and Western Africa and report it for the first time in Eastern Africa and in Rhipicephalus camicasi.ConclusionsThe presence of A. platys DNA in R. camicasi feeding on negative hosts together with the relatively high prevalence of A. platys, correlated with the absence of the probable vector Rhipicephalus sanguineus (s.l.) in Kenyan Island suggest the involvement of other tick species in the transmission of A. platys.

Occurrence of filaria in domestic dogs of Samburu pastoralists in Northern Kenya and its associations with canine distemper

Samples of blood (serum, smears and blood preserved with ethanol) were collected from dogs during a vaccination campaign in northern Kenya in the years 2006 and 2007. Blood was screened for filarial parasites using molecular and microscopy methods and sera were tested for antibodies against canine distemper virus (CDV). Parasitological examination revealed the presence of two species of canine filariae: Acanthocheilonema dracunculoides and A. reconditum. The DNA from the former species was detected in 58% dogs sampled in 2006 and 36% dogs sampled in 2007, whereas the latter was found only in 4.2% samples collected in 2007. Microfilariae were found in 33.8% blood smears collected in 2006 and 10.6% blood smears collected in 2007. The seroprevalence of CDV was 33.4% in 2006 and 11.2% in 2007. The effect of sex, age and CDV-seropositivity/seronegativity on the occurrence of A. dracunculoides was evaluated. Infection by A. dracunculoides was more common in males and in dogs with a positive antibody titer for canine distemper, but evenly distributed among different age groups. The difference in the prevalence of A. dracunculoides in two isolated mountain ranges was not statistically significant. Methodologies available for detection and determination of canine filariae are compared, underlining methodical pitfalls arising through the determination of less common filarial species. The role of single epidemiological factors and possible association between canine distemper and filariasis are discussed.

Relationship between the Prevalence of Ectoparasites and Associated Risk Factors in Free-Range Pigs in Kenya

A cross-sectional study was undertaken to determine the prevalence of ectoparasites and possible risk factors in free-range pigs from 135 farms of Busia District, Kenya. Three hundred and six pigs were examined for presence of external parasites using standard parasitological methods. Data on management practices including housing and history of acaricide spraying were also collected. The ectoparasites found in the pigs were Haematopinus suis (96.1%), Sarcoptes scabiei (63.7%), and ticks (29.7%). The tick species included Rhipicephalus appendiculatus (70%), Boophilus decoloratus (31%), and Amblyomma variegatum (12%). The occurrence of the infestations was associated with age, being highest in sows (S. scabiei) and finishers (ticks and H. suis). Male pigs had highest prevalences of H. suis and ticks, while female pigs had highest prevalence of S. scabiei. The prevalence of the parasitic infestations was significantly (P < 0.05) associated with their origin being either lower (H. suis and S. scabiei) or higher (ticks) in pigs originating from divisions with high rainfall. Housed pigs had significantly (P < 0.05) lower prevalence of H. suis and ticks than those from households without pig housing. It is concluded that the free-range pigs have high prevalence of ectoparasites, and effective control strategies focussing on improved animal husbandry and acaricide use should be implemented.