Abstract
Both TB and Kala-azar are highly endemic in Bangladesh, India, and other South East Asian
countries, where co-infections are reported. Visceral Leishmaniasis is usually human to human in
this region. The transmission has been suspected because parasites or circulating antibodies have
been detected in domestic animals in Indian subcontinent. The objective of this study was
epidemiological investigation relating to the concurrent infection between TB and Kala-azar, to
determine the Leishmania antibody in humans and animals, to identify MTB and Leishmania from
suspected patients and persons from few endemic areas through molecular tests, and to find out
the role of animals as reservoir in the transmission of Leishmanasis. This study was conducted at
Surya Kanto Hospital(SKH), and Kala-azar endemic areas of Trishal, Fulbaria, Madhupur and
Chatmohor Upazilla during Sep 2014 to Sep 2017. Human blood and spleen aspirations were
collected from patients admitted in SK Hospital and from people at endemic areas. Cattle blood
and spleen samples were collected from household cattle and those slaughtered in Qurbani Eid
ritual day from endemic areas. In admitted patients at SKH, in case of TB, 87.76% were in the
productive age of life and eighty percent (79.9%) were relatively in younger age group in
Leishmaniasis. In both diseases occupation of maximum respondents was found business with less
capital (75 – 83%) and day labourer 25 – 30%. Housing of 88 - 92% respondents were made of mud
and at least mud plasters, all were good for sandflies breeding. Majority (72 - 80%) of the
respondents had not sufficient monthly income (5000.00 to 10,000.00 BDT) of their family, poised
with 55 – 70% illiterate. About 85% respondents heard Kala-azar though people know more about
TB, and 92% respondents did not know the transmissibility of Kala-azar. Most of the respondents
(70%), did not know when sand flies bite. But people (75%) have become quite aware of using
mosquito nets. Temperature at study areas round the year varied within 7 to 36.5°C, annual
average humidity was over 70%. Three distinct peaks of Kala-azar seen in pre monsoon February,
monsoon September and post monsoon November may be the plethora of sand fly from June to
October. Soils were found alluvial in the areas with sand, silt and clay contents 18.09%, 44.78%,
36.88% respectively. Water contents of soil are important as well for sandfly breeding, where it
was 6.50 – 14.90% in the soil of human dwellings and 10.00 – 15.00% in the soil of cattle sheds. The
pH of soil in cattle sheds was found higher (8.90). The Carbon contents were found .92 to .98 Cmol
/kg of soil in study areas, are favourable for sandfly breeding. Detecting the concurrency, out of
total 300 patients 180 (60%) were found positive for TB. But after Gene Xpert 18(13.04%) were
detected positive from smear negative cases. Simultaneously from 140 Kala-azar suspects after
tested with rK39, ELISA and PCR 124 (95.4%) were detected positive for Leishmania and among all
these 10 (8.1%) were found positive for TB. From apparently 160 healthy local people 24(15%)
were found positive for Leishmania, 3.8% positive for TB. Cattle as reservoir, out of 170 cattle
20(11.8%) were found positive for leishmania antibody but none was positive for Leishmania DNA.
Out of 170 cattle 12 (7.1%) were found positive by Rapid test kit for TB. This study found TВ -
Kala-azar co-infection in Leishmania endemic areas in patients and apparently healthy community
people. In cattle blood anti Leishmania antibody was detected but none was found positive by PCR.
Studying cattle spleen, out of 110 cattle none was found positive for Leishmania by PCR. The
absence of Leishmania DNA is suggestive of no role of cattle as reservoirs in Bangladesh. Further
studies are recommended to investigate clinical, therapeutic and preventive implication of this
issues.