The Prevalence, Distribution and Economic Importance of Fasciolosis in Cattle, Sheep and Goats in Kenya

Abstract

Fasciolosis is a trematodc zoonotic disease of public health and economic importance. The disease in humans is hardly recognized by medical doctors and is rarely considered as a differential diagnosis among other parasitic infections. In humans it leads to hepatic damage hence occasioning the cost of hospitalisation and loss of human working hours. In animals it leads to mortalities, growth retardation, drop in production in livestock and condemnation of the infected livers at post mortem meat inspection (Meat control act, 1972). There has been a systematic and well co-ordinated effort in documenting the prevalence of fasciolosis in livestock in several countries of the world. However not much has been done in recent years in Kenya. No recent studies on the prevalence of fasciolosis in various species of domestic animals in the various provinces and districts of the country have been carried out, yet information from such studies is important in the planning and implementation of fasciolosis control programmes. It is particularly important in identifying the regions of the country to be given priority and species of animals to be targeted. Little effort has been put into determining the economic losses occasioned by fasciolosis in livestock in most countries of the world, Kenya included. The economic losses may be due to various factors, particularly important is the economic losses occasioned by the condemnation of liver fluke infected livers at slaughter. Lack of recent information on the prevalence and economic importance of fasciolosis in cattle, sheep and goats in Kenya necessitated the studies reported in this report. Using the post-mortem meat inspection records available in the Department of Veterinary Services, Kabete, a retrospective abattoir survey was carried out to determine the prevalence of fasciolosis in cattle, sheep and goats in Kenya, covering a period of ten years (1990-1999). The prevalence was calculated for all districts and then for each of the seven provinces of Kenya. The national prevalence was calculated from the pooled provincial data. A total of 5,421,188 cattle were slaughtered in Kenya during the 1990-1999 period. Out of these 427,931 had fasciolosis giving a national fasciolosis prevalence of 7.9%. Western province recorded the highest (16.1%) prevalence with 126,660 cattle found to be infected out of the 785,873 slaughtered. This was followed in a descending order by Eastern province (11.3%) with 599,900 cattle slaughtered and 67,881 infected, Nyanza province (8.9%) with 159,814 cattle slaughtered and 14,237 infected, Rift Valley province (8.3%) with 731,438 cattle slaughtered and 60,634 infected, Central province (6.1%) with 1,834,301 cattle slaughtered and 11 1,576 infected, Nairobi province (3.9%) with 314,758 cattle slaughtered and 12,248 infected and Coast province (3.5%), where 995,104 cattle were slaughtered and 34,695 infected. A total of 1,700,281 sheep were slaughtered in Kenya over the ten-years’ period, out of which, 61,955 were infected giving a national prevalence of 3.6%. Western province recorded the highest (10.1%) prevalence with 19,554 sheep found to be infected out of the 194,251 slaughtered. This prevalence was followed, in a descending order, by Nyanza province (8.7%) where 40,735 sheep were slaughtered and 3,560 had Fasciola infection, Eastern province (4.8%) where 168,207 sheep were slaughtered and 8,150 had Fasciola infection, Central province (3.5%) where 483,481 sheep were slaughtered and XV 16,852 had Fasciola infection, Rift valley province (2.6%) where 407,319 sheep were slaughtered and 10,704 had Fasciola infection, Nairobi province (0.9%) where 57,960 were slaughtered and 532 had Fasciola infection and Coast province (0.7%) where 348,328 were slaughtered and 2,603 had Fasciola infection. A total of 2,062,828 goats were slaughtered in Kenya from 1990-1999. Out of these, 48,889 were infected with Fasciola giving a national prevalence of 2.4%. The highest prevalence of 9.1% was recorded in Western province where 125,621 goats were slaughtered and 1 1,383 were infected. This was followed by Nyanza province (4.7%) where 72,686 goats were slaughtered and 3,428 had Fasciola infection, Central province (4.4%) where 211,325 goats were slaughtered and 9,351 had Fasciola infection, Eastern province (2.7%) where 499,266 goats were slaughtered and 13,475 had Fasciola infection. In the Rift Valley province, a total of 283,635 goats were slaughtered and 6,755 (2.4%) were infected, in Coast province 764,627 goats were slaughtered and 3,929 (0.5%) were infected and lastly in Nairobi province 105,668 goats were slaughtered and 568 (0.5%) were found to be infected. A cross-sectional survey was carried out in the outskirts of Nairobi's Dagoretti slaughterhouses where routine post-mortem meat inspection was done. All the liver flukes detected in cattle, sheep and goats were collected and transported to the laboratory for analysis to determine their species by observing their size and morphology. Out of the 1,584 cattle inspected, 147 (9.3%) had liver flukes. All the liver flukes collected from the 147 livers were identified as F. gigantica. Livers from a total of 989 sheep were inspected, out of which 8 (0.8%) had liver flukes. Livers from a total of 954 goats were inspected, out of which 4 (0.4%) had liver flukes. All the liver flukes xv i collected in Dagoretti from the three livestock species were identified as F. gigantica. The economic importance of fasciolosis in livestock was determined by calculating the loss, in monetary terms, occasioned by condemnation of infected livers. The data collected from the meat inspection records provided the number of livers condemned due to fasciolosis in cattle, sheep and goats slaughtered from 1990-1999. A monetary value was calculated for the livers condemned by multiplying the quantity (Kg) with the average market prices for the livers of the three livestock species. This revealed that, a total of Kshs. 201,436,470 was lost nationally due to condemnation of Fasciola infected livers. This represented a loss of Kshs. 192,568,950, Kshs. 4,956,400 and Kshs. 3,911,120 due to condemnation of cattle, sheep and goat livers respectively. The study observed a general down ward trend of the economic loss over the period 1990-1999, from Kshs. 21,557,520 in 1990 to Kshs. 16,221,530 in 1999. These results indicated that cattle had the highest prevalence of fasciolosis, followed by sheep and goats in a descending order. Western province had the highest prevalence of fasciolosis for cattle, sheep and goats, while Coast province had the lowest prevalence for all the species. The high prevalence of fasciolosis in livestock in Kenya, coupled with its economic and public health importance, calls for concerted control measures to be implemented in this country. The regions of the country showing the highest fasciolosis prevalence such as Western, Nyanza, Central and Eastern Provinces, should be given more attention when implementing the fasciolosis control programmes. Salvaging the residue value of condemned livers by using them to process pet foods xv i i after sterilisation can also reduce the heavy economic loss, revealed in this study. In addition, control of fasciolosis in livestock will lower the prevalence of the disease in slaughtered animals and therefore reduce the number of livers condemned at slaughter due to presence of Fasciola spp.