Danielle A Zacarias1, Nuno Rolão2, Flaviane A de Pinho3, Ingridi Sene1, Jailthon C Silva1, Teresinha C Pereira1, Dorcas L Costa4, Carlos H N Costa1. 1. Laboratório de Leishmanioses, Instituto de Doenças Tropicais Natan Portella, Universidade Federal do Piauí, Teresina, Brazil. 2. Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisboa, Portugal. 3. Setor de Patologia Animal, Centro de Ciências Agrárias, Universidade Federal do Piauí, Teresina, Brazil. 4. Departamento Materno-Infantil, Universidade Federal do Piauí, Teresina, Brazil.
Abstract
BACKGROUND: An infected host's Leishmania infantum load in blood is considered to be an estimate of his or her total parasite burden. Therefore, the measurement of blood parasite burden is important in the identification of factors involved in parasite control. METHODS: Quantitative polymerase chain reaction was performed on blood samples from 625 patients with kala-azar consecutively admitted to a reference hospital in Teresina, Brazil. Primers were used to amplify a segment of kDNA using the TaqMan system. Non-parametric statistical tests were applied. RESULTS: The median blood parasite burden was 499.2 amastigote equivalents (AE)/ml. Children <1 year old (yo) had a high parasite burden, which dropped sharply after the first year of life (192.8, AE/ml at 1 < 2 yo) and remained lower until adolescence. Following adolescence, the parasite burden increased with age, peaking among elderly individuals. Men had a higher parasite burden than women. HIV-infected patients had a much higher parasite burden than non-infected patients. The parasite burden of children under 5 years with acute moderate to severe malnourishment (weight-for-age and body mass index z-scores <-2) was almost three times greater than that of better-nourished children. The parasite burden identified in deceased patients was more than twice that of surviving patients; those with a higher risk of death, sepsis, pneumonia and jaundice also had increased parasite burdens. All of these differences were statistically significant at P-values <0.05. CONCLUSIONS: These data indicate that the parasite burden in patients with kala-azar was associated with age- and gender-associated factors and with HIV infection status. Acute malnutrition could be either a cause or a consequence of a higher parasite burden. An individual's parasite burden influences his or her clinical profile, disease severity and mortality risk. The best explanation for the presence of a higher parasite burden in individuals with these immunoregulatory conditions and severe disease is the occurrence of acquired immunosuppression followed by heightened innate immunity.
BACKGROUND: An infected host's Leishmania infantum load in blood is considered to be an estimate of his or her total parasite burden. Therefore, the measurement of blood parasite burden is important in the identification of factors involved in parasite control. METHODS: Quantitative polymerase chain reaction was performed on blood samples from 625 patients with kala-azar consecutively admitted to a reference hospital in Teresina, Brazil. Primers were used to amplify a segment of kDNA using the TaqMan system. Non-parametric statistical tests were applied. RESULTS: The median blood parasite burden was 499.2 amastigote equivalents (AE)/ml. Children <1 year old (yo) had a high parasite burden, which dropped sharply after the first year of life (192.8, AE/ml at 1 < 2 yo) and remained lower until adolescence. Following adolescence, the parasite burden increased with age, peaking among elderly individuals. Men had a higher parasite burden than women. HIV-infectedpatients had a much higher parasite burden than non-infected patients. The parasite burden of children under 5 years with acute moderate to severe malnourishment (weight-for-age and body mass index z-scores <-2) was almost three times greater than that of better-nourished children. The parasite burden identified in deceased patients was more than twice that of surviving patients; those with a higher risk of death, sepsis, pneumonia and jaundice also had increased parasite burdens. All of these differences were statistically significant at P-values <0.05. CONCLUSIONS: These data indicate that the parasite burden in patients with kala-azar was associated with age- and gender-associated factors and with HIV infection status. Acute malnutrition could be either a cause or a consequence of a higher parasite burden. An individual's parasite burden influences his or her clinical profile, disease severity and mortality risk. The best explanation for the presence of a higher parasite burden in individuals with these immunoregulatory conditions and severe disease is the occurrence of acquired immunosuppression followed by heightened innate immunity.
Authors: Ana Nilce S Maia-Elkhoury; Gustavo Adolfo Sierra Romero; Samantha Y O B Valadas; Marcia L Sousa-Gomes; José Angelo Lauletta Lindoso; Elisa Cupolillo; Jose Antonio Ruiz-Postigo; Daniel Argaw; Manuel J Sanchez-Vazquez Journal: PLoS Negl Trop Dis Date: 2019-12-19
Authors: Sarah Forrester; Amy Goundry; Bruna Torres Dias; Thyago Leal-Calvo; Milton Ozório Moraes; Paul M Kaye; Jeremy C Mottram; Ana Paula C A Lima Journal: Microbiol Spectr Date: 2022-04-06