Asymptomatic Leishmania infection in humans: A systematic review

Pederiva, Milena Menezes Corrêa; Santos, Sidney Mariano dos; Rivarola, Liz Graciela Sanabria; Guerreiro, Victor Jorge; Lopes, Katiana Simões; Lima, Manoel Sebastião da Costa; Neitzke-Abreu, Herintha Coeto

doi:10.1016/j.jiph.2022.12.021

Cited by 9 publications

(11 citation statements)

References 87 publications

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“…Our results show that a substantial proportion of FC (34.8%) and RC (36.4%) were asymptomatic at T2, and that a high proportion of FC had been asymptomatically infected at T1 (28.6%). There is no gold standard to define asymptomatic infections (28, 32). We based our definition of “asymptomatic infection” on at least one of two serological tests (rK39 and DAT) being positive, but not on PCR positivity.…”

Section: Discussionmentioning

confidence: 99%

“…Different ratios of asymptomatic to symptomatic infection have been shown, for example it was estimated at 5.6:1 in Ethiopia (29) and from 1.6:1 and 2.4:1 in Sudan (30). “Asymptomatic infection” is still not clearly defined (28, 31, 32), but is usually characterised by one or a combination of the following positive tests: serological tests, polymerase chain reaction (PCR) and cellular tests; in individuals who do not show any signs of disease and remain healthy (28, 32). However, at least one study has characterised individuals who had a past history of VL as asymptomatic (33).…”

Section: Introductionmentioning

confidence: 99%

“…Other tests that measure the adaptive immune response to Leishmania parasites are also used, such as the leishmanin skin test (LST), where Leishmania antigen is injected intradermally, and a Delayed-type hypersensitivity (DTH) reaction is used as a readout system (34); as well as activation of peripheral blood mononuclear cells (35) or whole blood cells (36) with Leishmania antigen. Both PCR and qPCR are also used (28, 32).…”

Section: Introductionmentioning

confidence: 99%

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Demographic characteristics and prevalence of asymptomaticLeishmania donovaniinfection in migrant workers working in an endemic area in Northwest Ethiopia

Yimer,

Takele,

Yizengaw

et al. 2024

Preprint

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Visceral leishmaniasis (VL), a neglected tropical disease that causes substantial morbidity and mortality, is a serious health problem in Ethiopia. Infections are caused byLeishmania(L.)donovaniparasites. Most individuals remain asymptomatic, but some develop VL, which is fatal if not treated.We identified the area of Metema-Humera in Northwest Ethiopia as a setting in which we could follow migrant workers when they arrived in an endemic area. The demographic characteristics of this population and factors associated with their risk of asymptomatic infection are poorly characterised. We divided our cohort into individuals who visited this area for the first time (first comers, FC) and those who had already been in this area (repeat comers, RC). We followed them from the beginning (Time 1, T1) to the end of the agricultural season (Time 2, T2), performing tests for sand fly bite exposure (anti-sand fly saliva antibody ELISA) and serology forLeishmaniainfection (rK39 rapid diagnostic test and the direct agglutination test) at each time point and collecting information on risk factors for infection.Our results show that most migrant workers come from non-endemic areas, are male, young (median age of 20 years) and are farmers or students.At T1, >80% of them had been already exposed to sand fly bites, as shown by the presence of anti-saliva antibodies. However, due to seasonality of sand flies there was no difference in exposure between FC and RC, or between T1 and T2. The serology data showed that at T1, but not at T2, a significantly higher proportion of RC were asymptomatic. Furthermore, 28.6% of FC became asymptomatic between T1 and T2. Over the duration of this study, one FC and one RC developed VL.In multivariable logistic regression of asymptomatic infection at T1, only age and the number of visits to Metema/Humera were significantly associated with asymptomatic infection.A better understanding of the dynamics of parasite transmission and the risk factors associated with the development of asymptomatic infections and potentially VL will be essential for the development of new strategies to prevent leishmaniasis.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Demographic characteristics and prevalence of asymptomaticLeishmania donovaniinfection in migrant workers working in an endemic area in Northwest Ethiopia

Yimer,

Takele,

Yizengaw

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…Different ratios of asymptomatic to symptomatic infection have been shown, for example it was estimated at 5.6:1 in Ethiopia ( 29 ) and from 1.6:1 to 2.4:1 in Sudan ( 30 ). “Asymptomatic infection” is still not clearly defined ( 28 , 31 , 32 ), but is usually characterised by one or a combination of the following positive tests: serological tests, polymerase chain reaction (PCR) and cellular tests; in individuals who do not show any signs of disease and remain healthy ( 28 , 32 ). However, at least one study has characterised individuals who had a past history of VL as asymptomatic ( 33 ).…”

Section: Introductionmentioning

confidence: 99%

Demographic characteristics and prevalence of asymptomatic Leishmania donovani infection in migrant workers working in an endemic area in Northwest Ethiopia

Yimer,

Takele,

Yizengaw

et al. 2024

Front. Epidemiol.

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IntroductionVisceral leishmaniasis (VL), a neglected tropical disease that causes substantial morbidity and mortality, is a serious health problem in Ethiopia. Infections are caused by Leishmania (L.) donovani parasites. Most individuals remain asymptomatic, but some develop VL, which is generally fatal if not treated. We identified the area of Metema-Humera in Northwest Ethiopia as a setting in which we could follow migrant workers when they arrived in an endemic area. The demographic characteristics of this population and factors associated with their risk of asymptomatic infection are poorly characterised.MethodsWe divided our cohort into individuals who visited this area for the first time (first comers, FC) and those who had already been in this area (repeat comers, RC). We followed them from the beginning (Time 1, T1) to the end of the agricultural season (Time 2, T2), performing tests for sand fly bite exposure (anti-sand fly saliva antibody ELISA) and serology for Leishmania infection (rK39 rapid diagnostic test and the direct agglutination test) at each time point and collecting information on risk factors for infection.ResultsOur results show that most migrant workers come from non-endemic areas, are male, young (median age of 20 years) and are farmers or students. At T1, >80% of them had been already exposed to sand fly bites, as shown by the presence of anti-saliva antibodies. However, due to seasonality of sand flies there was no difference in exposure between FC and RC, or between T1 and T2. The serology data showed that at T1, but not at T2, a significantly higher proportion of RC were asymptomatic. Furthermore, 28.6% of FC became asymptomatic between T1 and T2. Over the duration of this study, one FC and one RC developed VL. In multivariable logistic regression of asymptomatic infection at T1, only age and the number of visits to Metema/Humera were significantly associated with asymptomatic infection.ConclusionA better understanding of the dynamics of parasite transmission and the risk factors associated with the development of asymptomatic infections and potentially VL will be essential for the development of new strategies to prevent leishmaniasis.

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“…In East Africa, Nepal, Bangladesh and India, the anthroponotic form, produced by L. donovani, is predominantly found [2]. A study carried out in Brazil, using the CR technique, demonstrated a prevalence of asymptomatic leishmaniasis infection of up to 80% in the analysed dogs [12]. The processes of asymptomatic infection and the bodyʹs immunological reactions are not fully understood, which is why diagnostic methods must be adapted for each individual patient [13,14].…”

Section: Introductionmentioning

confidence: 99%

The Immune Response in Canine and Human Leishmaniasis and How This Influences the Diagnosis- a Review and Assessment of Recent Research

Martinescu¹

2023

Preprint

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Laboratory diagnosis of leishmaniasis remains a major challenge, demonstrating variable efficacy in detecting infected mammalian hosts. Thus, there is a great need for the accuracy of the identification of appropriate antigens to also improve diagnostic tests. This review brings to the fore the sensitivity of the balance in canine and human leishmaniasis, which greatly influences the progression of the disease and especially the diagnostic methods. The problem of diagnosis arises in asymptomatic leishmaniasis, since in these conditions the methods considered as reference in the diagnosis of leishmaniasis no longer show certainty, being influenced for the most part by the immune response of the host, which is different according to the presence of other associated diseases or even according to the breed, when we talk about dogs. Consequently, the diagnosis and surveillance of leishmaniasis cases remains an open topic, with the need for new methods adapted to the immunological status of the host.

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Asymptomatic Leishmania infection in humans: A systematic review

Cited by 9 publications

References 87 publications

Demographic characteristics and prevalence of asymptomaticLeishmania donovaniinfection in migrant workers working in an endemic area in Northwest Ethiopia

Demographic characteristics and prevalence of asymptomaticLeishmania donovaniinfection in migrant workers working in an endemic area in Northwest Ethiopia

Demographic characteristics and prevalence of asymptomatic Leishmania donovani infection in migrant workers working in an endemic area in Northwest Ethiopia

The Immune Response in Canine and Human Leishmaniasis and How This Influences the Diagnosis- a Review and Assessment of Recent Research

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