BRUCELLOSIS AND PUBLIC HEALTHSami Ullah Khan and Razia Kausar1 DVM, 10th Semester, FVS,UAF Departmentof Anatomy, FVS,UAF1Brucellosis is an infectious, contagious and economicallyimportant disease of primarily animals but also has zoonotic importance. OIEhas declared it as second most important zoonotic disease after rabies.Although it has been eradicated from many developed countries like Australia,Canada, Japan, New Zealand and European countries but it still has endemicityin Africa, Mediterranean, parts of Asia and Latin America. In Pakistan,prevalence of animal Brucellosis was reported only 0.
33-0.65% in 1967 butrecent studies have shown increased prevalence many folds. Due to its increasedprevalence in Pakistan, there are severe hazards to human health either throughdirect contact or through consumption of contaminated milk and dairy products, soit is necessary to conduct surveillance and to devise control programs forBrucellosis accordingly.Objective of this article is to highlight the zoonosis,etiology, transmission, clinical manifestations, and prevalence in Pakistan, ofBrucellosis in humans. For this purpose, knowing its features related toanimals, is an important aspect.
There is also a need to know bioterrorismpotential of Brucellosis. At the end, control strategies will be discussed tostop the increment of its prevalence in Pakistan. Being a veterinarian, it’sour responsibility to highlight all the zoonotic threats and their control tosave not only animals’ but also human’s lives.Causative Agent :Brucellosis is caused by Brucella abortus in cattle, Brucellamelitensis in goats, Brucella ovis insheep and Brucella suis in swine/pig.In Horse, disease is caused by Brucellaabortus. In a study conducted by University of Agriculture, seroprevalenceof brucellosis in horses was found nearly 20%.
In humans, disease is mainly caused by B. melitensis, called”undulant fever”, “Mediterranean fever” or “Malta fever”. There are certainmeasures which can be taken to prevent and treat infection in humans even inpersistence of infection in domestic animals. Transmission: Brucellosis is milk bornedisease, transmitted to human population due to persistence of infection indomestic animals, expansion of International travel and lack of hygienicmeasures in animal husbandry. People dealing with meat i.
e. slaughter-houseworkers, slaughter-men, butchers, meat packers, processors of hides, skin andwool and veterinarians, are more susceptible, called occupational risk. In thisaspect, families of farmers and animal breeders are also at higher risk. Organismgets entry through direct contact with infected animals or materials with skin abrasions.Human-to-human transmission, from lactating mothers to their breastfed infantsis rare but blood donation and tissue transplantation have higher significance.Transmission through inhalational route can be there due to contaminated dustand dried dung. Contaminated water by recently aborted fetus or run-off rainwater from endemic areas can be source of spread for Brucellosis in humanpopulation. Ingestion of fresh milk and dairy products likebutter, cream or ice-cream and cheese, is main source of transmission to humanpopulations.
In contrast, meat products are less frequently associated withtransmission due to their consumption after proper cooking. Raw vegetables canalso be contaminated by infected animals and be a hazard. Travelling to endemicareas and consuming contaminated foods, import the pathogen to disease-freeregion. Similarly, import of animals from endemic countries, becomes source ofintroducing disease in a country. Cattle, sheep, goat and camel are mainreservoirs for Brucellosis in Pakistan.Diagnosis: In humans as well as in animals, clinical picture ofbrucellosis is not specific or evident and diagnosis needs to be supported bylaboratory tests.
Disease is manifested by acute or sub-acute febrile illnessusually marked by an intermittent or remittent fever that’s why called”undulant fever” in humans. Fever is accompanied by headache, malaise,anorexia, prostration, arthralgia and back-pain. Patients feel better in themorning but symptoms worsen with the progression of a day. Signs and Symptoms: A research, conducted on humans regarding symptoms,has shown that 93% patients infected with Brucellosis had fever, 95% had lackof energy (prostration), 87% had sweats, 91% had aches (pain), 86% had back pain, 81% had headache, 78% hadlack of appetite, and 65% had weight loss. Other sign and symptoms observed wereabdominal pain, constipation, arthritis, cough, testicularpain/epididymo-orchitis, sleep disturbance, lymphadenopathy, splenomegaly, andhepatomegaly. Respiratory complications including hilar & para-tracheallymphadenopathy, interstitial pneumonitis, bronchopneumonia, lung nodules,pleural effusions, and empyema, have been reported in people working inabattoirs due to inhalational route of transmission.
In men, most pronouncedcomplications are orchitis and epididymitis. Endocarditis is majorcardiovascular complication reported in 2% people and can involve both nativeand prosthetic valve, most often involving aortic valve than mitral valves.In a case report from Morocco, complication of CNSi.e. meningitis was seen, resembling Tuberculosis meningitis. In this report,human patient admitted at emergency had chronic headache for 9 months with someepisodes of vomiting and intermittent fever.
Tuberculosis is endemic in Moroccobut results of lumber puncture, Magnetic Resonance Imaging (MRI) and especiallyserology confirmed the neuro-brucellosis, one of clinical manifestations ofBrucellosis.Brucella can involve any of the organ system of humanbody so diagnosis in human is difficult based on clinical picture. Due to widevariety of clinical manifestations other complications include osteo-articular,gastrointestinal, hepatobiliary, cutaneous and ophthalmic which can be seen inBrucellosis.Brucella is not only a zoonotic problem but also apotential agent of Bioterrorism “intentional use or threatened use ofbiological agents to hurt people, create fear or disrupt society”. Whenever, wetalk about the zoonosis “transfer of disease from animals to human” andbioterrorism “defined earlier”, then the importance of veterinarian, as anasset for any crisis or public health team, becomes obvious.
Veterinarians haveextensive knowledge of microbiological, chemical and physical health hazards offood animals. So veterinarians have to play major role in conducting surveillanceand devising control programs for Brucellosis.Brucella belongs to “Category B” as a biologicalweapon. Two species B. melitensis andB. suis are potential source ofbio-terrorism and have been developed experimentally as biological weapons bystate sponsored programs but no application in a bioterrorist attack has beenreported so far.
They both have higher stability in aerosol form and lowinfectious dose rate. These features make them suitable for the purpose ofbio-terrorism. Chances of attack to human and animal populations are higher inareas with low endemic rate. The organism can be obtained from natural sourcesso Health and veterinary authorities should be aware of this potential sourceof infection.
In Pakistan, the expected prevalence of Brucella suis is negligible but B.melitensis has higher prevalence in animals as well as humans.Researches have been conducted in different areas ofPakistan, for knowing the prevalence of human brucellosis. For this purpose,serological diagnostic tests like Rose BengalPrecipitation Test (RBPT), Standard Plate Agglutination Test (SPAT) and SerumTube Agglutination Test (STAT) are considered authentic but PCR (moleculartest) and ELISA are also conducted as confirmatory tests. A research conductedin Bhimber, a district of Azad Kashmir, in a year of 2013 has shown 9.33%,7.
33% and 6% prevalence of human Brucellosis by RBPT, SPAT and STAT,respectively. It was also concluded that prevalence was higher in females thanin males. Similar study was conducted in District Swat, KPK in a year of 2016,which had shown 3.66%, 2% and 2.66% prevalence of B. melitensis in human by SPAT, STAT and PCR diagnostic tests,respectively. Prevention and control: Brucellosis inhuman, can only be prevented effectively by elimination of animal reservoirs.
As described earlier, this elimination necessitates an interaction between themedical authorities concerned with public health and veterinary authorities. Thiscollaboration is first step in devising control programs, indicating concept of”One-world, One-health”. For successful outcomes, all sections of communityneed to be involved but provision of specialist expertise is responsibility ofmedical and veterinary authorities. They are responsible for diagnosis,treatment, surveillance and devising control programs accordingly.Prevention of diseasein human must be based on elimination of direct and indirect contact toinfected animals and their products, which is main source of spread. This canbe achieved by personal hygiene, adoption of safe working practices, protectionof the environment and food hygiene.
Use of vaccination for human has littlepart in prevention of human disease. Personal hygiene includes wearingprotective clothing, disinfection of clothes after use, disinfection offootwear, treating body cuts and wounds with antiseptics, protection of eyes byrinsing and using eye drops, use of respirators to avoid respiratorycontamination, and serological examination after a specific period. Farmsanitation/ adoption of safe working practices include fulfilling biosecurityrecommendations, wearing protective clothing to avoid contact with contaminatedmaterial e.
g. aborted foetus, disinfection of farm premises, incineration ofcollected material in leak-proof container, vehicle tyre dipping at farmentrance. Food hygiene include milkhygiene and meat hygiene. Milk and its products are source of contamination soboiling or high temperature pasteurization of milk is necessary for control ofBrucellosis in human. If pasteurization facilities are not available, heatingat 80-85 °C for several minutes is necessary to make milk safe for consumers. Transmissionof Brucella through meat isimpossible in Pakistan due to thorough or over-cooking of meat. Meatpreservation methods like drying, salting and smoking can’t kill the organism.Never consume under-cooked meat.
Brucellosis controlin animals is directly linked with Brucellosis control in humans. There arethree types of control measures in animals:a) Quarantine strategies at farm andcountry level.b) Sanitation and biosecurity measures atfarm.c) Herd immunity throughvaccination/immunization.Vaccination:There are three strains for vaccination programs i.
e. Strain-19 (S-19), RB-51and Rev-1. Strain-19 is used in Pakistan for vaccination which is importedbecause still there is no manufacturing of Brucella vaccine in Pakistan.Brucella vaccine is live, shouldn’t be used in pregnant animals. One of itsproperties is that it should be non-pathogenic for humans.Conclusion:Itis concluded that Veterinary department has parallel importance to the medicaldepartment when we talk about zoonotic diseases and public health.
These bothauthorities have to work in collaboration, involving whole community throughpublic health education and training of workers, to minimize the zoonosis,potential threats and to devise control strategies for any outbreak. Theemerging concept of “one-world, One-health” has made, importance ofveterinarians, obvious.