IMPACT OF BOVINE BRUCELLOSIS ON THE ECONOMY & PUBLIC HEALTH IN INDIA

January 18, 2022

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IMPACT OF BOVINE BRUCELLOSIS ON THE ECONOMY & PUBLIC HEALTH IN INDIA

Brucellosis is one of the most common but often neglected zoonotic diseases in the world . The disease occurs worldwide, except in some highincome countries . In low-income countries, the disease is often underreported and there is little or no effective control, resulting in major health, economic and livelihood burdens . The disease is caused by bacteria of the genus Brucella. Twelve species of Brucella have been identified so far . Most species of Brucella can infect multiple species of animals, including humans [6]. In cattle, the infection is predominantly caused by B. abortus, less frequently by B. melitensis and occasionally by B. suis . In sexually mature female cattle, infection localizes in the reproductive system and produces placentitis followed by abortion, causing production losses . Most infected animals abort only once in their lifetime, but may remain infected their entire life . The disease is often asymptomatic in non-pregnant female cattle and after the first abortion. Adult male cattle may develop orchitis, and brucellosis may cause infertility in both sexes. Hygromas can occur in leg joints and are a common manifestation of brucellosis in some tropical countries . Bovine brucellosis can also occur in buffaloes, bison and yak and clinical manifestations in these animals are similar to those in cattle . India, a country with more than one billion people, is the world’s leading milk producer, contributing around 17% of the world’s total milk production . India has the world’s largest dairy cattle population at around 300 million, both buffalos and cows . Dairy products are the main animal-source food for the large vegetarian population, and 70 million households engage in milk production . The cultural, religious and historical importance of cows in India, including the common ban to slaughter cattle and the free roaming, further adds a layer of complexity to disease control, and the predominance of an informal market of raw milk adds to the public health risks of people.

Brucellosis is an infectious, contagious disease of numerous animal species as well as humans. It is caused by bacteria of the Brucella genus. Six species (B. abortus, B. melitensis, B. suis, B. ovis, B. canis, B. neotomae) containing several biotypes are responsible for the natural infection of a number of animal species, including cattle, small ruminants, pigs, rodents and carnivores, as well as humans and other mammals. Although brucellosis is a disease of worldwide distribution, recognition of its health and economic importance differs from country to country. Although the public health importance of brucellosis is acknowledged throughout the world, the economic importance of animal brucellosis is felt most keenly by countries practising intensive livestock farming, as the disease not only causes production losses (from abortion, stillbirth, sterility, a longer calving interval and lower milk yields), it also constitutes a barrier to trade.

Brucellosis cause heavy economic losses to the livestock industry through abortion, premature birth, retained foetal membrane, decreased milk production, delayed conception and infertility. A real economic impact of this sub clinical disease remains to be estimated.

Brucellosis is an economically important zoonotic disease with worldwide distribution, with low-income countries being more affected. The disease is endemic in India, a country that house the world’s largest cattle and buffalo population and produce the most milk in the world. Prevalence of the disease in the country is reported as low as 1% to as high as 60% by different researchers but many of the published studies that reported higher prevalence were conducted in non-randomised samples. Based on this review, overall prevalence in the country is likely 12% or less. About 20 different risk factors are reported that contribute/predispose to occurrence of bovine brucellosis. The risk factors could be classified in four groups: host factors, farmer’s factors, managemental factors, and agro-ecological factors. Various studies reported high economic burden of the diseases in dairy animals but there is dearth of comprehensive and rigorous economic studies.

In the absence of highly effective vaccines and because of difficulties in executing a segregation and slaughter policy of infected animals in countries like India, control of bovine brucellosis remains a challenge.

India has the largest livestock population in the world and is world’s largest milk producer. According to the 19 Livestock Census (2012) country has about 190 th million cattle, 108 million buffaloes, 135 million goats, 65 million sheep and 10 million pigs. It accounted for about 57 percent of buffalo and 14 percent of the cattle population of the world. In India, dairy farming is becoming more intensive and organized, and farmers are adopting it for diversi&cation by each passing day due to continuous shrinkage of land holdings accompanied by various other socio-economic factors. Dairy animal population is increasing consistently and Livestock Census 2007 pegged the combined cattle and buffalo population at 303 million (198.3 million cattle and 104.7 million buffalo; USDA Foreign Agricultural Service Report, GAIN Report Number: dated: Sep.22, 2010).Reproductive pro&ciency is one of major consideration in any dairy or livestock production enterprise for sustainable pro&tability. Apart from mastitis, various reproductive disorders viz; endometritis, repeat breeding,abortions and retained placenta etc. are the main impediments to pro&tability in organized dairy farms in India. The causes of infertility and abortions are many, both speci&c and nonspeci&c. The speci&c agents contribute directly to manifestation of infertility leading to reproduction and production losses and role of many such etiologicalagents viz. spp., spp., Brucella Campylobacter Chlamydiapsittaci Listeria monocytogenes, Coxiella , burnetii Mycoplasma bovigenitalium, Salmonella , spp. and Leptospira spp has been well established (Radostitis et al., 2007). Among various reproductive infections of domestic animals, brucellosis is highly contagious bacterial zoonotic disease affecting both livestock and humans.It is considered to be true zoonoses (basically transmitted from animals to humans) and is one of world’s major zoonoses which are of veterinary, human, public health importance and of much economic concern in many parts of the world. It has been reported invariably all domestic animals, humans and also scarcely reported in wild animals and marine (Singh , 2015).

Brucellosis in livestock and humans is caused by various species of the genus , which are facultative, Brucella intracellular, gram negative coccobacilli that lack capsules, ‘agella and endospore. Brucellosis is usually caused by in cattle, or in B. abortus B. melitensis B. ovis small ruminants, in pigs and in dogs. Some B. suis B. canis species of contain biovars; nine for Brucella B. abortus, three for and B. melitensis B. suis &ve biovars for . In humans, it is transmitted from infected domestic animals and the causal bacteria are , , B. abortus B. melitensis B. suis (biovars 1-4) and rarely or marine mammal B. canis Brucella B. melitensis . In general, is the dominant causative agent of brucellosis in humans and is more infectious than , although disease caused by B. abortus B. abortus B. melitensis is indistinguishable to that of (Dokuzoguz , 2005). Live vaccines for et al. B. abortus, B. melitensis and B. canis M- strain of are also pathogenic for humans while , and biovar 5 B. ovis B. neotomae B. suis have not been reported to cause human disease. Cattle are susceptible once they have reached sexual maturity. Infection persists in the host once infected. The disease very often spreads from animal to animal in a herd by several modes of transfer, mainly by contact with infected discharges from an aborted dam and its fetus. Infection occurs by ingestion, penetration of the intact skin, conjunctiva and contamination of the udder during milking. The adult cattle may abort during late pregnancy. However, no obvious clinical signs/symptoms appear in brucellosis infected immature or non-pregnant animals. In cattle, causes abortions, stillbirths and weak B. abortus calves; abortions may occur during mostly during the late pregnancy (last trimester), associated with retention of placenta and reduced milk yield. Higher incidence of retention of placenta following abortions in such animals frequently leads to pyometra and death may occur as a result of acute metritis (Radostitis 2007). After the et al., &rst abortion, subsequent pregnancies are generally normal; however, female bovines may become carrier and shed bacteria in milk and uterine discharges. Brucellosis causes orchitis, epididymitis, seminal vesiculitis and sometimes testicular abscesses in affected bulls. Occasionally, hygromas particularly of leg joints develop in males and is common symptom observed in some tropical countries. Infertility occurs occasionally in both sexes due to metritis or orchitis/epididymitis. Affected animals may remain sterile for the entire life. Systemic signs usually do not occur in uncomplicated infections and deaths are rare except in the fetus or newborn. Although brucellosis is mainly implicated for inducing abortions in livestock, it signi&cantly causes reproductive losses. Considering the losses (approx. Rs 1.25 lakhs per abortion) due to brucellosis in terms of decreased milk production, abortions (loss of calf), reduced conception rates, weak offspring, reduced calf crop, weight loss, infertility, poor semen quality and lameness, it is one of the most serious diseases of livestock with great economic and public health importance and is a major impediment for the trade and export of animals, semen, meat and milk products (Gul and Khan, 2007). Zoonotic aspects and public health importance Brucellosis is an important but neglected emerging endemic zoonotic communicable disease in India. Farmer, veterinarians, shepherds, abattoir workers, milk plant and meat product plant personnel, hunters and livestock producers are always at high risk as an occupational hazard. Brucellosis is also one of the most easily acquired laboratory infections. It has been recognized as one of common laboratory transmitted infections particularly occurring in clinical, production and research laboratories ( ; Bouza , 2005 CDC, et al. 2008). In India, 742 million rural people residing in 638,588 villages and thousands of small towns remain in close contact with domestic and wild animals because of their dependence on animals for draught power, agriculture operations, milk and other animal products which make asizable Indian population at a greater risk of acquiring a zoonotic disease including brucellosis. The environment and the circumstances like poor sanitation and hygiene, poor socio-economic status, illiteracy, lack of awareness and poor health infrastructure and services are conducive for the spread of this disease in rural households than those in urban areas in India. Brucella spp. is of interest as they are categorized as biological agents due to their high contagiousness and impact on human and animal health. The zoonotic pathogens and were B. abortus, B. melitensis, B. suis designated as agents of Category ‘B’ by the Centre for Disease Control (CDC, Atlanta, USA). Another issue of concern is the use of as a biological weapon. Brucellae Although there is no reported case of bio-terrorism using Brucella spp. Brucellae (Shareef, 2006), nevertheless, are not dif&cult to grow and disperse (the American military weaponized in 1954). Brucella suis Bovine brucellosis, the most economically devastating reproductive disease in male and female is rapidly growing causing concern for the farmer, veterinarians, livestock supervisors and &nally farmer’s risk of his own family health. The transmission to humans may result in prolonged illness and long-term sequelae (Yagupsky and Baron, 2005). Brucellosis is a serious public health problem in many developing countries particularly, in regions of high endemicity such as Africa, the Mediterranean, the Middle East, parts of Asia and Latin America. Though brucellosis has been eradicated in many developed countries, it remains largely an uncontrolled and neglected disease in India. The main impact is economic; deaths are rare except in the fetus and neonate. The treatment of animal brucellosis is very expensive and often unsuccessful and compensation for slaughter of infected animals is not available.

Incidence/Prevalence of brucellosis

s Although brucellosis and its mode of transmission were discovered over 100 years ago, it remains a worldwide problem, predominantly so in developing countries. Prevalence of bovine brucellosis and transmission of infection to the human population has been signi&cantly decreased following effective vaccination-based control and prevention programmes with increased sero-surveillance and monitoring in many developed countries. However, it remains widely distributed throughout the developing world and is considered to be serious problem in at least 86 courtiers including India. Brucellosis is an uncontrolled problem in high endemic regions such as the Mediterranean, Middle East, Africa, Latin America and western Asia (Corbel, 1997; Refai, 2002) of the developing world. Bovine brucellosis is widespread in India and it was &rst recognized in 1942. The prevalence of brucellosis in different animal species varied widely and appears to be on the increase in recent times, perhaps due to increased trade of animals, meat and dairy products accompanied with intensi&ed farming practices. Verma (2000) et al. reported brucellosis ranging from 1.81 to 2.45 % in aborted and infertile small as well as large ruminants in Himachal Pradesh. The long term serological studies carried out by Renukaradhya . (2002) indicated 5 % of et al cattle and 3% of buffaloes to be infected with brucellosis in India. They further observed that cumulative incidence of this disease was 7.9 % in sheep and 2.2 % in goats in 10 of the 28 states. In a recent study, an overall seroprevalance of bovine brucellosis was recorded to be 22.18% (132/595) and 13.78% (82/595) by ELISA and RBPT, respectively in organized dairy farms with a history of abortion in different geographical zones of India (Trangadia , 2010). et al. Survey of the brucellosis from 1948 to 2009 indicates its prevalence in Indian cattle and buffalo to be ranging from 1.81 to 20.7% of the tested samples (Kumar, 2010). Serosurveillance studies conducted (using ELISA test) in PVK, LUVAS, Uchani in Karnal during 2009-2010 indicated that 73% cows and 80% of buffaloes having history of recent abortions and surprisingly 33% cows and 64% buffaloes from organized dairy farms with no history of abortions had brucellosis (Annual Report of Veterinary Unit, Karnal, 2009-10). The survey of ICAR’s PD-ADMAS Bangalore also indicated a rising trend in the prevalence of bovine brucellosis.

Factors responsible for spread of the disease

The factors responsible for the spread of Brucella organisms include sanitary, socioeconomic, animal husbandry, farming, political etc. In India animals roamed free for grazing and combined with different prevalent livestock get ample opportunity for intermixing through traditional animal husbandry systems which favoured the transmission of the infection. The changing and fast growing dairy industry in India has resulted in intensi&ed trade and animal movements, which provide a new and increased risk in spreading the infection (Renukaradhya et al., 2002). This uncontrolled animal transportation through “open” borders increases the risk for the spread of this diseasefromendemicto non- endemicareas. Brucella spp can survive for long period in aborted fetuses, soil, dairy products, meat, dust, dung manure, hay, water, slurry, equipments, wool and clothes. Moreover, in conditions of high humidity and low temperatures (no sunlight), organisms remain viable for several months. Brucella can withstand drying, particularly when organic material is present, and can survive in dust and soil. Survival is longer when the temperature is low, particularly when it is below freezing. Since Brucella organism survives in liquid nitrogen with semen straw and can spread rapidly through frozen semen being used for arti&cial insemination. The preponderance of natural bull service in rural areas especially in buffaloes is yet another important factor in the maintenance and spread of infection. As the infectious dose is very low (particularly of 10 organisms only), it is an high B. melitensis, occupational risk for farmers, veterinarians, abattoir workers, laboratory personnel, farm workers and others who work with animals and consume their products (Smits and Cutler, 2004). Crushing of umbilical cord of newborn kids or lambs with teeth by shepherds and skinning of stillborn lambs and kids and aborted bovine fetuses, which may have heavy spp. load, also Brucella present high occupational risk of brucellosis. Insuf&cient preventive measures and lack of adequate control programs further add to the spread of brucellosis. Although bacterial load in muscle tissues of affected animals is low, but consumption of customary/traditional raw or undercooked delicacies containing infective tissues or body secretions (liver) also contribute to human infections. Improper disposal (no burying or destruction) of abortion materials containing high load contribute to the spread of the Brucella infection. It is important to realize that open water sources such as ponds and wells become a source of infection by contamination with any infected material or Brucella wastewater from brucellosis infected farms. Human brucellosis was once thought to be predominantly transmitted through animal contact. However, it is now being increasingly realized that animal products such as milk and meat products are frequently the source of disease transmission (Kochar , 2007). et al. Dairy products prepared from unpasteurized milk such as soft cheese, yoghurts and ice-cream have high concentration of nd consumption of these is an Brucella a important source of transmission of this infection. The disease has been recognized as one of the common laboratory-transmitted infections and has been reported to occur in clinical, research, and production laboratories ( ; as accidental ingestion, Bouza , 2005 CDC, 2008) et al. inhalation and mucosal or abraded skin contact is a major health hazard for the laboratory workers handling cultures of virulent or avirulent attenuated strains. The increase in business and leisure travel to brucellosis-endemic countries has led to importation of the disease into nonendemic areas (Corbel, 2006).

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Economic impact, loss and cost of bovine brucellosis

Bovine brucellosis causes huge losses to the dairy industry; however, there is a dearth of comprehensive economic studies. It is also observed that terms such as economic impact, loss, and cost of brucellosis are used by some researchers loosely and interchangeably. Economic impact can include direct (e.g. reduced milk yield, increased mortality) and indirect (e.g. vaccination, culling) costs. Direct impacts may further be classified as visible (e.g. abortion, repeat breeding), invisible (e.g. lower fertility), additional costs (e.g. treatment, vaccination) and revenue forgone (e.g. distress selling) . Loss may comprise only those parameters that reduce benefits (e.g. reduced milk yield, reduced weight gain, reduced fertility, increased replacement cost, increased mortality etc.) while cost would comprise amounts spent for treatment and control (e.g. biosecurity, vaccination, movement control, disease surveillance, research etc.) of the disease . Most economic estimates have not taken into consideration the loss caused by distress selling, feeding and management loss of pregnant animals in the event of abortion, person-days loss for treating animals, cost of antiseptic and detergents, cost of transportation related to treatment, cost of diagnosis etc. Most studies extrapolate the economic figures based on limited epidemiological information and assumptions developed in the given country or elsewhere. Few studies that estimate the economic impact of the disease based on rigorous epidemiological data collected from a randomly selected population. Because of lack of uniformity in approach to measurement of economic impact/cost/ loss, and the fact that these are highly context specific, the estimates have also varied widely.

Preventive and control measures

Learning lessons from brucellosis free countries, countries like India where brucellosis is widespread in cattle and buffaloes measures to prevent the spread of this disease including statutory mass vaccination of livestock, constant monitoring and sero-surveillance of livestock population, improved animal husbandry practices etc. are required. The other methods of prevention are health education aimed at increasing awareness of risks, encouraging health promotion, disease prevention, intervention measures, implementation of local, regional and international standards related to food safety, enhanced regulations on the trading of animals and animal products at national and international levels. Animal owners should be taught about the importance of vaccination of their animals. At present mass vaccination and regular follow-up at village level, milk sample testing and maintaining vaccinated herds in villages and dairy farms and preventing entry of any infected animal and material are the effective ways to bring down the incidence of brucellosis in countries like India where test and segregate, culling/slaughter of infected animals is not practically fool proof and economically viable and for various socio-economic reasons. With ever increasing number of bull mother farms in the central and state setups and larger no of A.I. centers, accredited testing labs needed to be opened in more numbers. In India, 742 million people live in rural areas in 638,588 villages and thousands of small towns.About &ve million households in the country are engaged in the rearing of small ruminants (sheep and goats) and other allied activities. Hence, bovines and humans stand at a greater risk of acquiring zoonotic diseases including brucellosis from sheep and goat population also. The disease has an added importance in countries like India, where conditions are conducive for wide-spread human infection on account of unhygienic conditions and poverty. As brucellosis is transmitted from small ruminants, therefore, efforts are required to control brucellosis in goats and sheep. While effective control measures still need to be implemented, doctors and other health workers may help patients and risk groups to prevent brucellosis by teaching them essential methods to prevent exposure to the pathogen such as boiling of milk and to avoid the consumption of dairy products prepared from unpasteurized milk. Prevention of human brucellosis depends on control of the disease in domestic livestock. Also, control programme for human brucellosis would depend to a large extent on public health education about the risk factors involved in spread of disease, good administrative arrangement and ensuring the maximum co-operation between health and veterinary authorities. It is important to include brucellosis in public health education and to come out of a reductionist approach focused only from a veterinary perspective. At present, there is no national programme focusing on brucellosis. Little attention is given to curative services and livestock vaccination. Focus on prevention, health education and safe livestock practices awareness is also lacking. Most of the research work carried is laboratory-based, focusing on clinical aspects while ignoring the socio-cultural and other conditions responsible for the spread of brucellosis As there is no human vaccine, veterinarians and other high occupational risk persons should be made aware to take all the protective measures while handling abortions, still births, suspected infected materials and samples etc. In research and diagnostic laboratories, spp. should Brucella be handled under conditions of biosafety level 3 or higher. The impact of brucellosis in control programs and the consequence of their subsequent neglect has been demonstrated in Iran where incidence of animal brucellosis declined from 44% (1956) to 5% (1958)after taking suitable control program (Refai , 2002). et al. In endemic areas good hygiene measures including protective clothing/equipment are very important in preventing and reducing occupational exposure. Strict precautions should be taken to avoid contamination of the skin, inhalation or accidental ingestion of organisms when assisting at a birth, performing postmortem or while handling an aborted fetus or foetal membranes and ‘uids. Risky agricultural practices such as crushing the umbilical cord of newborn livestock with teeth or skinning aborted fetuses should be avoided. Animal vaccines of Strain 19 and Rev-1 should be handled with caution to B. melitensis avoid accidental injection or exposure. Adverse events have also been reported with RB 51 vaccine, B. abortus although it is safer than Strain 19. Occasionally, persistent infections after vaccination have been reported in domestic animals and animals may shed strains in the milk or aborted fetuses and can infect humans. Once brucellosis is suspected or diagnosed in a herd or farm, identi&cation of infected animals, eradication of the infected and carrier animals, preventive steps to inhibit transmission to healthy and susceptible as well as measures to prevent re-introduction of the diseased animals need to be done. The disinfection of premises and equipments plays an important role as a preventive and control measure. Brucella species are readily killed by most commonly available disinfectants including 70% ethanol, phenolic disinfectants, formaldehydes, hypochlorite solutions, isopropanol, iodophores, and xylene; however, their ef&cacy decreases in presence of organic matter and low temperatures. contaminated surfaces can be Brucella disinfected by 2% formaldehyde solution, 2.5% sodium hypochlorite, 20% freshly slaked lime suspension and 2- 3% caustic soda. Autoclaving clears contaminated equipment from Gamma irradiation (e.g. in Brucella. colostrum) and pasteurization also destroys . It is Brucella reported to persist for weeks in ice cream and for months in butter. This organism survives for very short periods in meat unless it is frozen.