Objective: The aim of this study is to provide an update on histoplasmosis in Southeast Asia (SEA) and the Indian subcontinent.
Methods: A thorough search of literature was made using different sets of keywords.
Results: The disease is commonest in North and Central America, SEA and Indian subcontinent being areas of low endemicity.From China, 300 cases were reported between 1990-2011, most of the cases, 75% of them occurring along the Yangtze River. Histoplasmin skin test positivity ranged from 6% to 50% in the different population groups tested. The number of cases reported from other SEA countries was Thailand- 233, Malaysia-76, Indonesia-48, and Singapore-21, only few or no cases reported in other countries. In the Indian subcontinent, 413+ cases have been reported from different parts of India, largest number from West Bengal, followed by Uttar Pradesh, Delhi, Rajasthan, and Maharashtra. The recent reports indicate a rising incidence of histoplamsosis in India. The number of cases from other countries in the Indian subcontinent was Bangladesh-27, Nepal-7, Pakistan -4, and Sri Lanka-5.Histoplasmin sensitivity surveys carried out in different parts of northern India between 1952 and 1979 recorded 0–12.3%. skin-test positivity. The clinical spectrum varied from mild influenza-like illness to acute pulmonary histoplasmosis with non-productive cough, chest pain, dyspnea, fever, myalgia, weight loss, malaise and fatigue. Progressive disseminated histoplasmosiswas mainly characterized by hepatosplenomegaly, generalized lymphadenopathy, anemia, weight loss, pulmonary symptoms being less prominent. Employing nested PCR, H. capsulatum was identified in 99 environmental samples including 88 from soil admixed with bat guano in Thailand. Information on natural habitats of H. capsulatum in the Indian subcontinent is restricted to its isolation from one sample of soil admixed with bat guano from a 300-yr-old building near Kolkata.
Conclusion: The burden of histoplasmosis in SEA and the Indian subcontinent remains undetermined due to in adequate laboratory facilities and insufficient training in medical mycology. There is need for comprehensive myco-epidemiological investigations employing molecular techniques.