brucellosis and leptospirosis

1. BRUCELLOSIS &
LEPTOSPIROSIS

2. BRUCELLOSIS: Introduction
 Major bacterial zoonosis
 Known as Undulant fever, Malta fever, Mediterranean Fever
 Transmitted to man: direct or indirect contact with animals
 Characterized by intermittent or irregular febrile attacks,
with profuse sweating, arthritis and an enlarged spleen
 Severe disease and a disease of animals with serious
economic consequences

3. BRUCELLOSIS: Problem Statement
 Recognized public health problem with worldwide distribution
 Endemic wherever cattle, pigs, sheep and goats are raised in large
numbers
 Mediterranean zones, Europe, Central Asia, Mexico and South
America
 INDIA: Reported from practically every State in India
 No statistical information is available about the extent of infection in
various parts of the country
 Prevalence is difficult to estimate
 Many cases remain undiagnosed either because they are in apparent or
physicians are unfamiliar with the disease

4. BRUCELLOSIS: Epidemiological
Determinants
 AGENT FACTORS
 Agent:
 small, gram-negative rod shaped, non sporing, non motile and
intracellular coccobacilli of genus Brucella
 4 species: B.melitensis, B. abortus, B. sulis and B. canis
 B.melitensis: most invasive and most virulent, usually infects goat and
occasionally sheep
 B. abortus: less virulent and a disease of cattle
 B. sulis: intermediate virulence and chiefly infects pigs
 B. canis: parasite of dogs

5. BRUCELLOSIS: Epidemiological
Determinants
 Reservoir of Infection:
 Main: cattle, sheep, goats, swine, buffaloes, horse, dogs
 Abortion, premature expulsion of fetus or death
 Infected animals excrete Brucella in urine, milk, placenta, uterine and
vaginal discharges particularly during birth or abortion
 Animals may remain infected for life
 HOST FACTORS
 Disease of adult males
 Farmers, shepherds, butchers and abattoir workers, veterinarians and
laboratory works : occupational exposure
 Immunity follows infection

6. BRUCELLOSIS: Epidemiological
Determinants
 ENVIRONMENTAL CONDITIONS
 Most prevalent under conditions of advanced domestication of
animals in the absence of correspondingly advanced standards of
hygiene
 Overcrowding of herds, high rainfall, lack of exposure to sunlight,
unhygienic practices in milk and meat production
 Infection can travel long distance in milk and dust
 The organism can survive for weeks, or months in favorable
conditions of water, urine, faeces, damp soil and manure

7. BRUCELLOSIS: Mode of
Transmission
 Transmission is usually from infected animals to man
 No evidence of transmission from man to man
 CONTACT INFECTION:
 direct infection from infected tissues, blood, urine, vaginal discharge, aborted
fetuses and placenta
 Abraded skin, mucosa or conjunctiva
 Spread largely occupational, persons involved in handling livestock and slaughter
house workers
 FOOD BORNE INFECTION
 Indirectly by ingestion of raw milk or dairy products from infected animals
 Fresh raw vegetables can carry infection : grown in soil containing manure from
infected animals
 Water infected with excreta of infected animals

8. BRUCELLOSIS: Mode of
Transmission
 AIR BORNE INFECTION
 Inhalation of infected dust or aerosols
 INCUBATION PERIOD
 Usually 1-3 weeks, as long as 6 months
 PATTERN OF DISEASE
 May vary from an acute febrile illness to a chronic ill defined low grade
disease, lasting for several days, months and occasionally years
 Sudden onset of illness with swinging pyrexia, rigors, sweating,
arthralgia involving larger joints, low back pain, headache, insomnia,
small firm splenomegaly and hepatomegaly, leucopenia with relative
leucocytosis

9.  If treated with tetracycline: symptoms may disappear quickly, but the
infection being intracellular: persist giving rise to sub acute and
relapsing disease
 20% patients: symptoms recur for prolonged periods
 Diagnosis: isolation of organisms from cultures of blood, bone marrow
, exudates and biopsy specimens during acute phase of disease and
serological tests

10. BRUCELLOSIS: Control of Brucellosis
 IN THE ANIMALS
 Test and Slaughter:
 Case finding is done by mass surveys
 Skin tests are available
 Complement fixation test is recommended
 Animals infected are slaughtered with compensation to farmers
 Vaccination:
 Vaccine of B. abortus strain 19- young animals
 Compulsory vaccination for all the heifers on a yearly basis: reduce
the rate of infection
 Hygienic Measures
 Clean sanitary environment for animals, sanitary disposal of urine and
faeces, veterinary care of animals and health education

11.  IN THE HUMANS
 Early Diagnosis and Treatment:
 Uncomplicated cases: Tetracycline
 For adults in acute stage: 500 mg every 6 hours for 3 weeks
 Skeletal or other intramuscular complications: streptomycin 1g in
addition to tetracycline
 Pasteurization of Milk:
 Protective Measures:
 Farmers, shepherds, milkmen, abattoir workers
 Exercise care in handling and disposal of placenta, discharges and
fetuses
 Protective clothing while handling carcasses
 Exposed areas should be washed and soiled clothing renewed
 Vaccination:
 Human live vaccine of B. abortus strain 19-BA is available
BRUCELLOSIS: Control of Brucellosis

12. LEPTOSPIROSIS: Introduction
 Animal infection by serotypes of Leptospira (Spirochetes) and
transmitted to man under certain environmental conditions
 Manifestations are many and varied, ranging in severity from mild
febrile illness to severe and sometimes fatal disease with liver and
kidney involvement
 Weils disease is one of the manifestations of human leptospirosis

13. LEPTOSPIROSIS: Problem Statement
 Most widespread of disease transmissible from animal to man
 High prevalence in warm humid tropical countries
 Outbreaks result as a result of heavy rainfall and consequently heavy
flooding
 Global burden of disease : unknown
 >500,000 cases expected each year
 Incidence in some cases: 975 cases per lac population
 Strong links between leptospirosis and extreme weather events in
Guyana, India, Philippines and Thailand etc

14. LEPTOSPIROSIS: Epidemiological
Determinants
 AGENT FACTORS
 Agent:
 Thin and light motile spirochetes 0.1-0.2µm wide
and 5-15µm long with hooked ends
 Only stains of L.interrogans are pathogenic
 Organisms are visible by dark field illumination and silver staining
 23 serotypes and 200 serovars recognized
 Related by cross reactivity
 Source of Infection:
 Excreted in urine of infected animals
 Animal Reservoirs:
 Affect wild and domestic animals worldwide esp rodents like rats, mice and
voles
 Domestic animals: grazing in areas contaminated with urine of carrier host

15. LEPTOSPIROSIS: Epidemiological
Determinants
 HOST FACTORS
 Age:
 Children acquire infection from dogs more frequently than adults
do.
 Human infection is incidental
 Occupation:
 Infection is due to accidental exposure to the urine of infected
animals(farmer, workers in rice fields, sugarcane fields,
underground sewers, abattoir workers, meat and animal handlers,
veterinarians etc.)
 Swimming and fishing
 Immunity: Solid serovar specific immunity follows infection

16. LEPTOSPIROSIS: Epidemiological
Determinants
 ENVIRONMENTAL FACTORS
 Contact with an environment contaminated with urine
and faeces from carrier animal or other infected
animals.
 Leptospira shed in urine can survive for weeks in soil
and water
 Poor housing, limited water supply, inadequate
method of waste disposal

17. LEPTOSPIROSIS: Mode of
Transmission
 DIRECT CONTACT:
 Skin abrasions, intact in mucous membrane by direct contact with
urine and tissue of infected animal
 INDIRECT CONTACT:
 Contact of broken skin with soil, water or vegetation contaminated
with soil of infected animal or through ingestion of food and water
contaminated with leptospirae
 DROPLET INFECTION:
 Inhalation while milking infected cows or goats by breathing air
polluted with droplets of urine
 DIRECT MAN TO MAN INFECTION IS RARE
 INCUBATION PERIOD: 10 days (4-20days)

18. LEPTOSPIROSIS: Diagnosis
 Isolation of leptospires from blood during acute illness and from urine
after first week
 Dark field examination of the organism or culture in semi-solid
medium
 Urine: 10 day-6 weeks
 Serological Tests: Agglutination tests: positive after 7-10 days of
illness
 Indirect haemagglutination, immunoflorescent antibody and ELISA
 IgM ELISA: Early diagnosis (2 days)
 New Leptodipstick is also avaliable

19. LEPTOSPIROSIS: Control
 ANTIBIOTICS:
 Penicillin is the drug of choice (6 million units daily I.V)
 ENVIRONMENTAL MEASURES:
 Preventing exposure to potentially contaminated water, reducing
contamination by rodent control and protection of workers in
hazardous occupation.
 Measure taken to control rodents, proper disposal of wastes and health
education
 VACCINATION:
 Farmers and pets
 Incorporate strains of serotypes that predominate in a particular area
since immunity to one type of Leptospira may not protect against
infection by another