Leishmania Infections in India and Nepal
Author Information
Author(s): Ostyn Bart, Gidwani Kamlesh, Khanal Basudha, Picado Albert, Chappuis François, Singh Shri Prakash, Rijal Suman, Sundar Shyam, Boelaert Marleen
Primary Institution: Institute of Tropical Medicine, Antwerp, Belgium
Hypothesis
What is the relationship between L. donovani infection and clinical disease in high-endemic areas of India and Nepal?
Conclusion
Asymptomatic L. donovani infections are nine times more frequent than symptomatic VL disease, with about 1 in 50 latent infections leading to VL within 18 months.
Supporting Evidence
- 42 VL cases and 375 asymptomatic seroconversions were recorded in the first year.
- The infection:disease ratio was 8.9 to 1 in the first year.
- 7 extra cases of VL were observed in the seroconverters group during the 18 months' follow-up.
- 85% of asymptomatic seroconverters turned seronegative again within a year.
- Recent seroconversion was a strong risk factor for developing VL.
- The average incidence rate of VL over 30 months was 2.8/1000 PY.
- Incidence of VL in year 2 was significantly lower than in year 1.
Takeaway
In places where Leishmania is common, many people get infected without getting sick, and some of these infections can turn into a serious illness later.
Methodology
The study followed 21,267 individuals in high-endemic villages over 30 months, using DAT seroconversion to assess infections and clinical follow-up for VL cases.
Potential Biases
Potential bias due to reliance on serological testing and the absence of other diagnostic methods.
Limitations
The study relied on a single serological test (DAT) and did not explore cellular immunity.
Participant Demographics
49.1% women; 17.0% under five years of age; 42.6% under fifteen.
Statistical Information
P-Value
p<0.0001
Confidence Interval
95% CI: 1.9–2.9
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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