zoonotic tuberculosis in elephanths
Post on 11-May-2015
395 Views
Preview:
DESCRIPTION
TRANSCRIPT
ZOONOTIC TUBERCULOSIS in ELEPHANTS
Dr Sakshi Dubey, MVSc. Scholar, EpidemiologyDr. Bhoj R Singh, Principal Scientist & Head, Division of EpidemiologyIVRI, Izanagar, Bareilly, UP, India
Tuberculosis
One of the most ancient diseases of mankind and animals A contagious zoonotic disease Aristotle was first to say that tuberculosis is an airborne
disease. In 1865 Jean Antoine Villemin, put out the idea that TB
was genetically inherited. In1882 Robert Koch proved Villemin wrong by discovering
the bacterium causing the disease. It is caused by Mycobacterium spp.
Indian scenario
Endemic in most parts.Holds about 21% of the total global TB
cases1000 Indians die from TB per day. (Krishnaswami,
2000) One third of the population is suffering
from TB.
Global Scenario
2nd most common infectious cause of deaths (WHO 2013)
Human TB (zoonotic 3-10%) - localized in High Burden Countries (India, China, Indonesia, Nigeria, Bangladesh, and Pakistan)
22 High Burden Countries including India house for 80 % of all new TB cases.
In developing countries ~10.5% of human cases are associated with M. Bovis (ILRI,2012).
GLOBAL TB PROGRAMME
Estimated number of cases
Estimated number of deaths
1.4 million*(1.3–1.6 million)
8.7 million(8.3–9.0 million)
Up to 0.5 million
All forms of TB
Multidrug-resistant TB
HIV-associated TB 1.1 million (13%) (1.0–1.2 million)
430,000(400,000–460,000)
Source: WHO Global Tuberculosis Report 2012 * Including deaths attributed to HIV/TB
The Global Burden of TB -2011
Unknown, but probably > 150,000
Incidence rates, 2011 ( WHO )
Highest rates in Africa, linked to high rates of HIV infection~80% of HIV+ TB cases in Africa
Per 100 000 population≥300
150–29950–149
0–2425–49
Prevalence in Animal
Overall, 7.4% of livestock Bovines: 8%,camels 11%,Sheep and goats 2%Pigs 15%, Wildlife 5%
(ILRI,2012)
Tuberculosis in wild animals
A number of cases reported among wild animals worldwide.
In zoo primates TB is due to M. tuberculosis and M. bovis
In Larger land mammals (Ungulates), TB is mostly caused by M. bovis.
M. tuberculosis is the main cause of TB in Elephants, Rhinoceroses, Tapirs, and in some exotic bovine spp.
Tuberculosis in wild animals
TB in a chimpanzee at London zoo reported by Owen (1961)
TB in Tigers of Delhi and Darjeeling Zoos (Rathore and Khera, 1981)
TB in Lions of zoological garden Bombay (Das and Jayaro, 1986)
M. tuberculosis reported in some exotic carnivores and Psittacine birds.
Tuberculosis in wild animals
Wildlife Reservoirs
of TB
Eurasian badger (Meles meles) UKWhite-tailed deer (Odocoileus virginianus) USA
Wild boar (Sus scrofa) Spain
Cape buffalo (Syncerus caffer) Africa
Brush-tailed possum (Trichosurus vulpecula) New Zealand
(Wilson et al., 2009)
Tuberculosis in Elephants
Described in Asian documents of over 2000 years old
1st report of TB in elephants made in London zoo in 1875
Sporadic TB in Asian elephants and 1st case in African elephant reported in mid 20th century (Gorovitz, 1962)
During 1997 transmission of TB between human and elephants reported (Michalak et al., 1998)
Epidemiology
Though it is also found in free ranging animals, tuberculosis found more commonly in captive animal worldwide.
In Asian elephants mostly M. tuberculosis and M. bovis are involved.
(Abraham et al., 2010 and Mikota et al., 2007)Female seems to be affected more than the male
elephants (Karthik, 2012)
Prevalence of TB in Asian elephants is about 15% in India and 13% in Nepal
(Abraham et al., 2010 and Mikota et al., 2007)
In United States of America (USA), its prevalence in elephants is 6.3%
(Mikota et al., 2000)
The transportation is possible between the elephants by the way of trumpeting and trunk spray.
Transmission to elephants Humans activity can lead to an increased
level of M. tuberculosis being shed into the environment and may result in the spillover of infection into wildlife populations
(Mikota, 2008)
Development of TBInhalation of bacteria
Bacteria reach lungs, enter macrophages
Bacteria reproduce in macrophages
Lesion begins to form (caseous necrosis)
Bacteria cease to grow;lesion calcifies
Activated macrophages
reactivation
Immune suppression
Lesion liquifies Bact coughed up in sputum
Spread to blood,organs
death
Clinical signs
No typical signs in elephantNon specific signs includes:
InappetanceWeight lossSubcutaneous ventral oedema(Kay et. al. 2010)
Zoonotic aspects
By aerosolization my spread to:Elephant handlersZoo employees, veterinarians Other animals
Pathology
Involves primarily :Lungs Thoracic & Bronchial lymph nodesExtra thoracic sitesCaseous and mucopurulent exudates in trunk
Histological findings:
Epethelioid granulomas with giant cellPyelogranulomatous pneumonia
Diagnosis
Intra-dermal Tuberculin Test Microscopic examination
Acid Fast Staining Serological test
Elephant TB STAT-PAK® AssayMulti-antigen print immunoassay (MAPIA)ELISA
Molecular testPCR
Isolation and identification of Mycobacterium speciesSample: Trunk wash, Blood/Serum“Triple sample method”Lowenstein Jensen medium
TREATMENT
S. No. Drug Does (mg/kg)
Route Target conc. (µg/ml)
1. Ethambutol 30 Oral 2-5
2. Isoniazid 5 Oral/rectal 3-5
3. Pyrazinamide 30 Oral/rectal 20-60
4. Rifampin 10 Oral 8-24
(Guideline for control of tuberculosis, 2008 and Peloquin et al., 2006)
Dose and route of administration of Anti-Tubercular drugs in Elephants
• Standard protocol includes:
• 2 months with Isoniazid, Rifampin, Pyranzinamide & Ethambutol
• followed by 4 months of isoniazid and rifampicin (Daly et al.,
2006)
Tuberculosis Management Options
Conclusion
TB is endemic in captive elephants
The role played by elephants in the spread of TB to humans needs to be addressed.
Regular screening of elephants for TB is required for control.
Research on tuberculosis in elephants is required
top related