Changing trends in visceral leishmaniasis: 10 years' experience at a referral hospital in Nepal.

Visceral leishmaniasis (VL) is mainly confined to the southeast area in the Terai region of Nepal. This study aimed to assess time trends and geographical distribution of VL at a referral hospital over a 10-year period in Kathmandu, Nepal. A total of 1521 patients were admitted to the hospital during the study period (April 1999 to March 2009). Overall, 88% of cases were from endemic areas and 10% were from non-endemic areas. There was a significant decreasing trend in the number of VL cases in this hospital during the study period. However, VL is being increasingly diagnosed in patients from non-endemic areas of Nepal. Whether VL in non-endemic areas is imported or autochthonous remains to be elucidated. This study therefore reinforces the need for urgent VL and entomological surveillance in newly reported areas to allow effective VL control strategies to be developed for the future.