OBJECTIVES: Recent epidemiological reports indicate that asymptomatic human infections with Leishmania donovani, the causative agent of visceral leishmaniasis or Kala-azar (KA), occur frequently in India. We explored markers of infection. METHODS: Blood samples were collected from 286 healthy subjects from 16 villages in the Muzaffarpur district of Bihar. These individuals were classified into three groups: (i) persons with no history of KA and living in a house where no KA cases were previously reported, (ii) persons with no history of KA but living in a house where KA cases were diagnosed at the time of sampling or in the past, and (iii) successfully treated KA patients. Each sample was tested using a Leishmania-specific PCR to detect Leishmania DNA, and two serological tests to demonstrate anti-Leishmania antibodies: the Direct Agglutination Test and rK39 ELISA. RESULTS: PCR positivity was similar among the three groups (20-25%). In contrast, among treated patients, the percentage of serologically positive individuals was roughly five times that of healthy individuals with no KA history, as measured with either test. Living in a house where KA had been reported did not affect seropositivity. CONCLUSION: A significant proportion of asymptomatic infections of Leishmania exist in endemic regions. Using a combination of molecular and serological tests increases the capacity to detect infections at different stages. Further work is required to understand the kinetics of the markers.
OBJECTIVES: Recent epidemiological reports indicate that asymptomatic human infections with Leishmania donovani, the causative agent of visceral leishmaniasis or Kala-azar (KA), occur frequently in India. We explored markers of infection. METHODS: Blood samples were collected from 286 healthy subjects from 16 villages in the Muzaffarpur district of Bihar. These individuals were classified into three groups: (i) persons with no history of KA and living in a house where no KA cases were previously reported, (ii) persons with no history of KA but living in a house where KA cases were diagnosed at the time of sampling or in the past, and (iii) successfully treated KA patients. Each sample was tested using a Leishmania-specific PCR to detect Leishmania DNA, and two serological tests to demonstrate anti-Leishmania antibodies: the Direct Agglutination Test and rK39 ELISA. RESULTS: PCR positivity was similar among the three groups (20-25%). In contrast, among treated patients, the percentage of serologically positive individuals was roughly five times that of healthy individuals with no KA history, as measured with either test. Living in a house where KA had been reported did not affect seropositivity. CONCLUSION: A significant proportion of asymptomatic infections of Leishmania exist in endemic regions. Using a combination of molecular and serological tests increases the capacity to detect infections at different stages. Further work is required to understand the kinetics of the markers.
Authors: Milena de Paiva-Cavalcanti; Rayana Carla Silva de Morais; Rômulo Pessoa-E-Silva; Lays Adrianne Mendonça Trajano-Silva; Suênia da Cunha Gonçalves-de-Albuquerque; Diego de Hollanda Cavalcanti Tavares; Maria Carolina Accioly Brelaz-de-Castro; Rafael de Freitas E Silva; Valéria Rêgo Alves Pereira Journal: Cell Biosci Date: 2015-06-17 Impact factor: 7.133