Pakistani Soil is Positive for Agent of Tularemia
Soil microbes are beneficial for agriculture, waste management, natural and semi natural environment and water industry but as a natural reservoir of pathogenic organisms, attraction of soil fades away.
Some soil borne organisms have been used in history as a bio weapon. Bio weapon is an illegal use of biological warfare agents including bacteria, viruses, fungi, protozoa and toxins which cause panic in human and loss of animals and plants in minimum time period.
On the basis of public health preparedness, potential dissemination and level of incapacitation, bio warfare agents could be categorised as Variola major, Bacillus anthracis, Yersinia pestis, Clostridium botulinum (botulinum toxins), Francisellatularensis, Filoviruses and Arenaviruses belonged to category A while Coxiellaburneti, Brucella spp, Burkholderia mallei and Burkholderiapseudomallei placed to category B.
Tularemia is a disease of animals and humans caused by the bacterium Francisellatularensis.Francisellatularensisis a true soil pathogen and causes zoonotic disease in over 250 species of mammals.
Due to its high virulence, has encouraged usage of Francisellatularensisas a bio-weapon in different wars in the past.
Globally the organism has been isolated from water, soil, animals, human, amoeba, ticks, etc, but there has been no report from the South Asian countries like Pakistan.
Penn State University, PA, USA, sub-awarded funds to University of Veterinary and Animal Sciences (UVAS), Lahore, under an international collaborative research project titled “Spatial ecology and epidemiology of soil borne bacterial pathogens and their impact on human and animals” to understand distribution pattern of Francisellatularensis in selected districts of Pakistan and its associated risks of infection on the basis of its ecology.
The collaborating universities and institutions in this multi-disciplinary project includes Quaid-i-Azam University, Islamabad, GC University, Lahore, University of the Punjab, Lahore, Agha Khan University, Karachi, Livestock & Dairy Development Department, Punjab, Naval Medical Research Unit, Frederick, MA, USA and Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, USA. In Pakistan this research group was headed by Professor Dr Masood Rabbani, Dean, Faculty of Veterinary Science, UVAS, Lahore.
In the current project, a total of 2280 soil samples, representing 456 villages of eight districts of Pakistan, were collected from way-points having human-animal interaction, and tested through real time PCR to gauge the presence or absence of Francisellatularensis.
Association of risk factors was determined from data such as gender and age of animals, plough method, irrigation system, fertiliser type used, availability of veterinary services, level of farmer education, physical and chemical composition of the soil. Moreover, sero-prevalence against Francisellatularensis in cattle, buffaloes, sheep and goats was determined using ELISA.
Around 74 soil samples (3.24 per cent) were found positive for Francisellatularensis. DNA analysis showed 100 percent similarity with Francisellatularensissub specie holarctica reported from other regions like USA, Sweden, Spain, Turkey and Germany. Presence of Francisellatularensis in soil showed negative association with increase in number of human density. Cattle and buffalo were found more positive for antibodies against Francisellatularensisas compared to goat and sheep. Whereas, factors like: rain-irrigation system, lack of veterinary services and use of organic fertilizer have positive association with presence of antibodies against Francisellatularensis in the serum. Antibodies againstFrancisellatularensis in the animals were found more positive in animals where soil has more quantity of clay. It is recommended that similar studies may be done in other parts of Pakistan to have spatial distribution of Francisellatularensis all over Pakistan. The outcomes of the study shows that Francisella tularensis although present in the soil of Punjab province yet it is not of virulent type which can cause any epidemic in the country. In future studies, other sources of transmission like water, ticks and rodents may be considered with soil for complete analysis.
On the basis of results of present study, soil of Pakistan do contain human and animal pathogens and may need further investigation. Food crops grown on infected or contaminated soil can carry such life threatening pathogens which might cause panic death in animals.
Farmers, veterinarian, government organisations and stakeholders are advised to get the soil checked for bacterial pathogens before constructing any animal shed and farm at the selected premises. Local pathogens of your area could be different from other areas. Why not get a personalized vaccination schedule for your livestock which might get you wider coverage against pathogens and cost effective vaccination schedule.
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