Brucellosis, Tetanus & Plague By Dr. Riaz Ahmed
Brucellosis Also known as undulant fever / malta fever / mediterranean fever. Bacterial zoonosis which is transmitted to man by direct / indirect contact with animals. Caused by different species of brucella- group of organisms and characterized by:• Intermittent / irregular febrile attacks• Arthritis / enlarged spleen etc.
Epidemiology Agent factors:• Brucella abortus – in bovine – abortus fever• B.Suis – Pigs – Swine – F or Porcine• B.Canis – Canines – Canine fever• B.Melitensis – Goats – Caprine fever Host factors: predominantly disease of males.• Farmers• Shepherds• Butchers• Slaughter house men• Veterinarians• Lab-workers – are at special risk because of occupational exposure.
Environmental factors:Most prevalent under conditions of advanced domestication in the absence of corresponding advanced S.O. Hygiene (+) where there is• Overcrowding of herds• Increased rain fall• Lack of exposure to sunlight• Unhygienic practice of milking/ heat production
Lab diagnosis:• Bacteriological• Serological / allergic test Control: in animals:• Test / slaughter• Vacc – B.Abortus strain – 19• Hygienic measures In humans:• At individual level• At community level
Tetanus An acute disease caused by exotoxins of clostridium tetani clinically characterized by :• Muscular rigidity• Painful paraoxysmal spasms of voluntary muscles esp. Masseters ( trismus / lock-jaw ) Facial (risus sardonicus) Back / neck (opisthotonus)And those of lower limbs and abdomeno Mortality : 40-80%
Agent factors:• Clostridium tetani• Reservoir of infection• Source – soil / dust• Exotoxin• P.O.C – None Host factors:• Age / sex• Occupation• Rural / urban differences• Immunity Environmental factors:• Tetanus is a positive environmental hazard. M.O.T: contamination of wounds with tetanus spores.
I.P: 6 – 10 days Types:• Traumatic• Puerperal• Otogenic• Idopathic• Tetanus Neonatorum (8th day syndrome) Prevention:• Active immunization – DPT• Passive – ATS• Both• Antibiotics• Observe tetanus schedule for pregnant women
Plague (Black Death) Basically & primarily a zoonotic disease caused by Yersinia pestis involving rodents & fleas. It exists in natural foci & is transmitted by infected flea bites to humans living or intruding into the same ecological environment. Occurrence: many forms e.g.,• Epizootic• Enzootic• SporadicAnd in epidemics of all forms including anthroporotic primarily pnemonic.
History Epidemics of plague are mentioned in Bible Association of plague with rats is known to be ancient. 1st out-break – 1320 B.C. 1st Pandemic – 542 A.D. called Justinian plague, which lasted for 50 years & estimated mortality was 100 deaths. 2nd Pandemic – 1346 B.C. lasted for 30 years & claimed one forth world mortality. In 1840 B.C. – Pandemic of pneumonic type In 1930 – 6 million deaths in India. In 1994 - out-break in India, then subsided gradually.
Plague Def: Highly fatal disease characterized by high fever, progressive heart failure & nervous symptoms.o Conjunctiva is injected with reddish appearance.o Skin – hemorrhage & pustular eruptions. Clinical forms:• Bubonic• Pnemonic• Septicemic• sylvatic
Bubonic plague Onset sudden, most common type High temperature, prostration Painful buboos Vesicular / pustular skin lesions Complications: secondary terminal pneumonia
Pneumonic plague Primary P. Plague is rare. Generally follows as a complication of bubonic - septicemic plague. Incidence decreased 1% Highly infectious Symptoms – acute bacterial infection Sputum – hemorrhagic Most deadly form of plague
Septicemic :• Rare• Buboes absent• Fever – low• Hemorrhages into skin Sylvatic :• Endemic in rodents in jungles• Man is affected accidentally while doing activities like hunting etc.
Source of infection: In bubonic plague : by bite of inf. Rat – fleas Xenophsylla cheopis Xenophsylla actia Xenophsylla braziliensis In pneumonic plague: exhaled droplets of saliva sputum of patients Reservoir : rats & wild rodents, out of 1700 species 200 associated with plague.
I.P:• Bubonic : 2-7 days• Septicemic : 2-7 days• Pneumonic : 1-3 days P.O.C: pneumonic is very communicable from person to person, bubonic if terminal inf. is there. M.O.T:• Bubonic plague – bite of infected rat flea• Pneumonic plague – droplets
Epidemiology Agent factors: yersinia pestis, occur in blood, buboes, spleen, liver, other viscera of infected persons. Host factors:• Age / sex – all ages & both sexes• Activities of man e.g., hunting, cultivation, grazing, harvesting, construction etc.• Movements – ship, land, cargo• Immunity – no natural immunity Environmental factors:• Season : september – May• Temp : 20-25 C• Humidity less than 60%, Rain fall• Rural / urban, Human dwellings
Population at risk:• Geologists, Biologists• Anthropologists• Hunters, agriculturists etc. Vector of plague: Pulex irritants (human fleas) Blocked / Partially blocked flea Flea Indices:o Total flea indexo Specific index – if >1o Sp.% of fleaso Burrow index
Prevention & Control Control of cases:• Early diagnosis• Notification• Isolation• Treatment• Disinfection Control of fleas/ rodents:Application of insecticides, rodenticides and other preventive measures to be adopted. Vaccination: 0.5-1ml SC after 7-10 days.
Chemoprophylaxis: Surveillance Health education