Review Article, J Vet Sci Med Diagn Vol: 10 Issue: 7
Review on Status of Small Ruminant Brucellosis in Ethiopia
Adem Edao Heyi *
Department of Physics, Addis Ababa University, Addis Ababa, Ethiopia
Adem Edao Heyi
Department of Physics, Addis Ababa University, Addis Ababa, Ethiopia
Received Date: September 21, 2021; Accepted Date: October 06, 2021; Published Date: October 13, 2021
Citation: Adem Edao Heyi (2021) Review on Status of Small Ruminant Brucellosis in Ethiopia. J Vet Sci Med Diagn 10:7.
Brucellosis in small ruminants is mainly caused by Brucella meltiness and B. ovis and in sporadic cases by B. abortus. This disease is mainly characterized by abortion with the development of yellowish, sticky layers on the placenta in females. In male animals, it causes orchitis and epididymitis, and arthritis in both genders. Species of Brucella are obligate parasites, requiring an animal host for maintenance. They are small, non - motile, non - sporulating, non-toxigenic, aerobic, facultative intracellular, gram-negative coco-bacilli parasites. The primary route of dissemination of Brucella is the placenta, fetal fluids and vaginal discharges expelled by infected animal after abortion or full-term parturition. Brucellosis is readily transmissible to humans, causing acute febrile illness – undulant fever – which may progress to a more chronic form and can also produce serious complications affecting the musculoskeletal, cardiovascular, and central nervous systems. Humans get infected mainly by drinking unpasteurized milk and/or exposure to aborted fetuses, placentas or infected animals and by an occupational risk. Status of small ruminant brucellosis is not well addressed in Ethiopia. Studies conducted indicate that the prevalence of the disease is high in lowlands as compared with middle and highlands. Since brucellosis has no effective treatment; vaccination, test and slaughter, hygiene and awareness creation are the best alternative strategies.
Keywords: Brucellosis; Ethiopia; Small ruminant
Goats and sheep are important domestic animals highly adaptable to broad range of environmental conditions and fulfill a number of economic and social functions. According to statistics from the Central Statistical Agency, Ethiopia has over 39.89 million head of sheep and 50.5 million goats . In spite of the presence of huge small ruminant (sheep and goat) population, Ethiopia fails to optimally utilize this resource as a sector. Among the different factors which limit the economic returns from small ruminants’ production, reproductive diseases such as brucellosis are the major ones particularly in the pastoral areas.
Brucellosis is an infectious bacterial disease caused by members of the genus Brucella. It is disease of worldwide importance and affects a number of animal species. Brucellosis in small ruminants is mainly caused by Brucella melitensis (B.melitensis) and B. ovis in and sporadic case by B.abortus. This disease is mainly characterized by abortion with the development of yellowish, sticky layers on the placenta in females. In male animals, it causes orchitis and epididymitis, as well as inflammation of the joints and bursa. The consequences of brucellosis in small ruminants are: infertility, a high mortality rate in lambs and kids, mastitis, reduced milk production. The presence of small ruminant brucellosis in Ethiopia is well established similar to other reports elsewhere it imposes tremendous economic loss due to reproductive wastages such as infertility, abortion, stillbirth, and the likes. On the other hand, the pastoralist communities who have daily contact with their animals and use their products in their dietary habits are being infected by brucellosis .
The epidemiology of small ruminant brucellosis and its awareness various from one area to another so control measures appropriate in one area is not necessarily of value in another. Hence, it is essential to have adequate knowledge of the epidemiology and awareness of the disease before contemplating control programmes. In Ethiopia some studies have been conducted on small ruminant brucellosis at different times.
Brucellosis is an infectious bacterial disease caused by microorganisms of the genus Brucella, a coccobacillus, gram negative, facultative intracellular pathogen, which affecting a number of animal species. In small ruminants, brucellosis is mainly caused by B.melitens and B. ovis and in sporadic cases B.abortus. B. meltiness is most commonly infects sheep and goats while B. ovis primarily affects sheep. B. melitensis is most common source of human brucellosis.
Small-ruminant brucellosis is common in tropical area where animal production is commonly practiced and almost it has been eradicated from industrialized country like Europe. The prevalence of the disease is most frequently occurred in adult sheep and goats than younger one).
Species and breeds factor- goats are at higher risk of acquiring Brucella infection than sheep. This may be due to the greater susceptibility of goats to Brucella infection. Male animals are less susceptible to Brucella infection than females, due to presence of low concentration of erythritol in male relative to female animals.
Prevalence of small ruminant brucellosis is high in large flock size than small size flock. Mixing different species of animals (sheep/goat/ cattle) together has also a great factor to increase incidence of brucellosis . Brucellosis can transmit between animals through direct or indirect contact with diseased animals and their discharges Ingestion of food and water contaminated with brucella containing uterus discharge, aborted fetus and placenta are the way of getting brucellosis into flocks. The disease can also acquire through venereal transmission between adult and in kids and lambs by milk sucking and by in vitro transmission.
Due to its high accuracy, complement fixation is used as confirmatory test for B. abortus, B. melitensis, and B. ovis infections and it is the reference test recommended by the OIE for international transit of animals.
Status of small ruminant brucellosis in Ethiopia
Studies conducted on small-ruminant brucellosis in Ethiopia have indicated that sero-prevalence of the disease is varied from place to place ranging from 0.07 % in Somali region to 12.35% in Afar region which might be due to the differences in animal production and management systems as well as reasonably difference in agro- Ecological conditions of the study places and see .
Reports indicated that the prevalence of small-ruminant brucellosis was much higher in area where farmers practice the communal use of grazing land than in clan-based flock/herd segregation areas. This might be due to mixing animals from various areas in communal grazing system and watering points.
Public importance of small ruminant brucellosis
Since there is close contact between humans and their livestock,Brucellosis is readily transmissible to humans, causing acute febrile illness undulant fever which may progress to a more chronic form and can also produce serious complications affecting the musculoskeletal, cardiovascular, and central nervous systems which sometimes share the same housing enclosures, brucellosis is a significant health risk for the entire community.
Brucellosis is readily transmissible to humans, causing acute febrile illness undulant fever which may progress to a more chronic form and can also produce serious complications affecting the musculoskeletal, cardiovascular, and central nervous systems.
Brucellosis is a zoonotic bacterial disease caused by Brucella spp. and is primarily a disease of animals whereas humans are accidental hosts . The disease is one of the most widespread zoonotic and is endemic in many countries.
It is also considered a neglected zoonotic by the WHO. There are six identified species and numerous biotypes. From these species B. meltiness causes disease primary among sheep and goats and is also the most pathogenic for humans.
The bacteria show a strong host preference although crossspecies infections happen, particularly with B. meltiness.
Control and prevention
Control of brucellosis can be achieved by using vaccination to increase the population’s resistance to the disease.
The B. melitensis REV 1 vaccine is an attenuated strain of B. melitensis and an effective method to reduce the prevalence of brucellosis among whole flocks or herds.
In endemic countries humans get infected mainly by drinking unpasteurized milk/cheese and/or exposure to aborted fetuses, placentas or infected animal’s discharges and causes acute febrile illness-undulant fever-which may progress to a more chronic form and can also produce serious complications affecting the musculoskeletal, cardiovascular, and central nervous systems due. There is an occupational risk to veterinarians, abattoir workers and farmers who handle infected animals and aborted fetuses or placentas. Brucellosis is one of the most easily acquired laboratory infections, and strict safety precautions should be observed when handling cultures and heavily infected samples, such as products of abortion.
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