scholarly journals Canine Leishmaniosis Control through the Promotion of Preventive Measures Appropriately Adopted by Citizens

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Giulia Simonato ◽  
Erica Marchiori ◽  
Federica Marcer ◽  
Silvia Ravagnan ◽  
Patrizia Danesi ◽  
...  
Keyword(s):  
Leishmania Infantum ◽  
Preventive Measures ◽  
Sand Fly ◽  
Local Administration ◽  
Canine Leishmaniosis ◽  
Collaborative Approach ◽  
Serological Tests ◽  
Health Authorities ◽  
Northeastern Italy ◽  
Dog Owners

Canine leishmaniosis (CanL) is a disease caused by the protist Leishmania infantum and transmitted to dogs by sand fly (Diptera: Phlebotominae) bites. In 2005, a new autochthonous focus of CanL was recognised in the southern part of Euganei hills (northeastern Italy). In subsequent years, this outbreak was monitored, testing dogs and evaluating sand fly population. Moreover, dog owners were sensitized on the adoption of preventive measures, thanks to the collaboration of local administration, health authorities, and private veterinarians. This study includes serological tests on dogs, questionnaires submitted to dog owners regarding the use of preventive measures on their animals, and the evaluation of sand fly abundance. Data collected were statistically compared with those of previous years. The canine seroprevalence was significantly lower than that recorded at the beginning of the outbreak, despite the fact that sand fly abundance did not significantly decrease. In addition, most of the dog owners declared using regularly the topical insecticides on their dogs during the sand fly season. This experience demonstrated that a collaborative approach among scientific researchers, local authorities, and private veterinarians can achieve excellent results in the management of a leishmaniosis outbreak.

scholarly journals Canine leishmaniosis in Tunisia: Growing prevalence, larger zones of infection

2021 ◽  
Vol 15 (12) ◽  
pp. e0009990
Author(s):  
Ali Bouattour ◽  
Amine Amri ◽  
Jaber Amine Belkhiria ◽  
Adel Rhim ◽  
Ons Fezaa ◽  
...  
Keyword(s):  
Leishmania Infantum ◽  
Environmental Changes ◽  
Climatic Factors ◽  
Arid Zone ◽  
Present Report ◽  
Clinical Signs ◽  
Sand Fly ◽  
Canine Leishmaniosis ◽  
Age Group ◽  
Bioclimatic Zone

Background Discovered by Nicolle and Comte in 1908 in Tunisia, Leishmania infantum is an intracellular protozoan responsible for zoonotic canine leishmaniosis (CanL) and zoonotic human visceral leishmaniasis (HVL). It is endemic in several regions of the world, including Tunisia, with dogs considered as the main domestic reservoir. The geographic expansion of canine leishmaniosis (CanL) has been linked to global environmental changes that have affected the density and the distribution of its sand fly vectors. Methodology/Principal findings In this study, a cross-sectional epidemiological survey on CanL was carried out in 8 localities in 8 bioclimatic areas of Tunisia. Blood samples were taken from 317 dogs after clinical examination. Collected sera were tested by indirect fluorescent antibody test (IFAT; 1:80) for the presence of anti-Leishmania infantum antibodies. The overall seroprevalence was 58.3% (185/317). Among positive dogs, only 16.7% showed clinical signs suggestive of leishmaniosis. Seroprevalence rates varied from 6.8% to 84.6% and from 28% to 66% by bioclimatic zone and age group, respectively. Serological positivity was not statistically associated with gender. The presence of Leishmania DNA in blood, using PCR, revealed 21.2% (64/302) prevalence in dogs, which varied by bioclimatic zone (7.3% to 31%) and age group (7% to 25%). The entomological survey carried out in the studied localities showed 16 species of the two genera (Phlebotomus and Sergentomyia). P. perniciosus, P. papatasi, and P. perfiliewi were the most dominant species with relative abundances of 34.7%, 25% and 20.4%, respectively. Conclusions/Significance The present report suggests a significant increase of CanL in all bioclimatic areas in Tunisia and confirms the ongoing spread of the infection of dogs to the country’s arid zone. Such an expansion of infection in dog population could be attributed to ecological, agronomic, social and climatic factors that affect the presence and density of the phlebotomine vectors.

scholarly journals Leishmaniosis in Rodents Caused by Leishmania infantum: A Review of Studies in the Mediterranean Area

2021 ◽  
Vol 8 ◽  
Author(s):  
M. Magdalena Alcover ◽  
M. Cristina Riera ◽  
Roser Fisa
Keyword(s):  
Leishmania Infantum ◽  
Mediterranean Area ◽  
Molecular Techniques ◽  
Domestic Dog ◽  
Sand Fly ◽  
Mammalian Host ◽  
Canine Leishmaniosis ◽  
Transmission Cycle ◽  
Domestic Cycle ◽  
The Mediterranean

Leishmaniosis infection begins when a phlebotomine sand fly vector inoculates pathogenic protozoan parasites of the genus Leishmania into a mammalian host. In the case of Leishmania infantum, the domestic dog is considered to be the main parasite reservoir, and canine leishmaniosis (CanL) has a high mortality rate in untreated dogs. Hundreds of cases of human leishmaniosis (HL) are reported in the world each year, the incidence in Europe being relatively low. Leishmaniosis control is primarily focused on the dog, combining methods that prevent sand fly bites and boost host resistance to infection. However, these measures are only partially effective and new solutions need to be found. One of the main factors limiting CanL and HL control is the existence of a sylvatic Leishmania transmission cycle that interacts with the domestic cycle maintained by dogs. It is suspected that the main reservoir of infection in wildlife are rodents, whose expansion and rapid population growth worldwide is increasing the risk of human and zoonotic pathogen transfer. The aim of this review is therefore to analyze reports in the literature that may shed light on the potential role of rodents in the leishmaniosis transmission cycle in the Mediterranean area. Following the general methodology recommended for reviews, six databases (Google Scholar, Ovid, PubMed, Science Direct, Scopus and Web of Science) were explored for the period January 1995 to December 2020. The results extracted from 39 publications that met the established inclusion criteria were analyzed. It was found that 23 species of rodents have been studied in nine countries of the Mediterranean basin. Of the 3,643 specimens studied, 302 tested positive for L. infantum infection by serology, microscopy and/or molecular techniques.

scholarly journals Odour of domestic dogs infected with Leishmania infantum is attractive to female but not male sand flies: Evidence for parasite manipulation

2021 ◽  
Vol 17 (3) ◽  
pp. e1009354
Author(s):  
Monica E. Staniek ◽  
James G. C. Hamilton
Keyword(s):  
Leishmania Infantum ◽  
Etiologic Agent ◽  
Human Infection ◽  
T Test ◽  
Sand Fly ◽  
Lutzomyia Longipalpis ◽  
Sand Flies ◽  
Control Female ◽  
Behavioural Experiments ◽  
Paired T Test

Globally visceral leishmaniasis (VL) causes thousands of human deaths every year. In South America, the etiologic agent, Leishmania infantum, is transmitted from an infected canine reservoir to human hosts by the bite of the sand fly vector; predominantly Lutzomyia longipalpis. Previous evidence from model rodent systems have suggested that the odour of infected hosts is altered by the parasite making them more attractive to the vector leading to an increased biting rate and improved transmission prospects for the pathogen. However, there has been no assessment of the effect of Le infantum infection on the attractiveness of dogs, which are the natural reservoirs for human infection. Hair collected from infected and uninfected dogs residing in a VL endemic city in Brazil was entrained to collect the volatile chemical odours present in the headspace. Female and male Lu. longipalpis sand flies were offered a choice of odour entrained from infected and uninfected dogs in a series of behavioural experiments. Odour of uninfected dogs was equally attractive to male or female Lu. longipalpis when compared to a solvent control. Female Lu. longipalpis were significantly more attracted to infected dog odour than uninfected dog odour in all 15 experimental replicates (average 45.7±0.87 females attracted to infected odour; 23.9±0.82 to uninfected odour; paired T-test, P = 0.000). Male Lu. longipalpis did not significantly prefer either infected or uninfected odour (average 36.1±0.4 males to infected odour; 35.7±0.6 to uninfected odour; paired T-test, P = 0.722). A significantly greater proportion of females chose the infected dog odour compared to the males (paired T-test, P = 0.000). The results showed that the odour of dogs infected with Le. infantum was significantly more attractive to blood-seeking female sand flies than it was to male sand flies. This is strong evidence for parasite manipulation of the host odour in a natural transmission system and indicates that infected dogs may have a disproportionate significance in maintaining infection in the canine and human population.

scholarly journals Leishmania infantum Infection Modulates the Jak-STAT Pathway in Lutzomyia longipalpis LL5 Embryonic Cells and Adult Females, and Affects Parasite Growth in the Sand Fly

2021 ◽  
Vol 2 ◽  
Author(s):  
Erich Loza Telleria ◽  
Daisy Aline Azevedo-Brito ◽  
Barbora Kykalová ◽  
Bruno Tinoco-Nunes ◽  
André Nóbrega Pitaluga ◽  
...  
Keyword(s):  
Post Infection ◽  
Leishmania Infantum ◽  
Janus Kinase ◽  
Sand Fly ◽  
Lutzomyia Longipalpis ◽  
Sand Flies ◽  
Embryonic Cells ◽  
Adult Females ◽  
Parasite Survival ◽  
Stat Pathway

Phlebotomine sand flies (Diptera, Psychodidae) belonging to the Lutzomyia genus transmit zoonoses in the New World. Lutzomyia longipalpis is the main vector of Leishmania infantum, which is the causative agent of visceral leishmaniasis in Brazil. To identify key molecular aspects involved in the interaction between vector and pathogens and contribute to developing disease transmission controls, we investigated the sand fly innate immunity mediated by the Janus kinase/signal transducer and activator of transcription (Jak-STAT) pathway in response to L. infantum infection. We used two study models: L. longipalpis LL5 embryonic cells co-cultured with L. infantum and sand fly females artificially infected with the parasite. We used qPCR to follow the L. longipalpis gene expression of molecules involved in the Jak-STAT pathway. Also, we modulated the Jak-STAT mediated immune response to understand its role in Leishmania parasite infection. For that, we used RNAi to silence the pathway regulators, protein inhibitor of activated STATs (PIAS) in LL5 cells, and STAT in adult females. In addition, the pathway suppression effect on parasite development within the vector was assessed by light microscopy in late-phase infection. The silencing of the repressor PIAS in LL5 cells led to a moderate increase in a protein tyrosine phosphatase 61F (PTP61F) expression. It suggests a compensatory regulation between these two repressors. L. infantum co-culture with LL5 cells upregulated repressors PIAS, suppressor of cytokine signaling (SOCS), and PTP61F. It also downmodulated virus-induced RNA-1 (VIR-1), a pathway effector, indicating that the parasite could repress the Jak-STAT pathway in LL5 cells. In Leishmania-infected L. longipalpis females, STAT and the antimicrobial peptide attacin were downregulated on the third day post-infection, suggesting a correlation that favors the parasite survival at the end of blood digestion in the sand fly. The antibiotic treatment of infected females showed that the reduction of gut bacteria had little effect on the Jak-STAT pathway regulation. STAT gene silencing mediated by RNAi reduced the expression of inducible nitric oxide synthase (iNOS) and favored Leishmania growth in sand flies on the first day post-infection. These results indicate that STAT participated in the iNOS regulation with subsequent effect on parasite survival.

scholarly journals Distinct gene expression patterns in vector-residing Leishmania infantum identify parasite stage-enriched markers

2019 ◽  
Author(s):  
Iliano V. Coutinho-Abreu ◽  
Tiago D. Serafim ◽  
Claudio Meneses ◽  
Shaden Kamhawi ◽  
Fabiano Oliveira ◽  
...  
Keyword(s):  
Leishmania Infantum ◽  
Developmental Stages ◽  
Expression Patterns ◽  
Principal Component ◽  
Sand Fly ◽  
Parasite Development ◽  
Lutzomyia Longipalpis ◽  
Specific Marker ◽  
Limited Information ◽  
Natural Sand

AbstractPromastigotes of Leishmania infantum undergo a series of extracellular developmental stages inside the natural sand fly vector Lutzomyia longipalpis to reach the infectious stage, the metacyclic promastigote. There is limited information regarding the expression profile of L. infantum developmental stages inside the sand fly vector, and molecular markers that can distinguish the different parasite stages are lacking. We performed RNAseq on unaltered midguts of the sand fly Lutzomyia longipalpis after infection with L. infantum parasites. RNAseq was carried out at various time points throughout parasite development. Principal component analysis mapped the sequences corresponding to the procyclic, nectomonad, leptomonad or metacyclic promastigote stage into distinct positions, with the procyclic stage being the most divergent population. Transcriptional levels across genes varied on average between 10- to 100-fold. Comparison between procyclic and nectomonad promastigotes resulted in 836 differentially expressed (DE) genes; between nectomonad and leptomonad promastigotes in 113 DE genes; and between leptomonad and metacyclic promastigotes in 302 DE genes. Most of the DE genes do not overlap across stages, highlighting the uniqueness of each stage. Furthermore, the different stages of Leishmania parasites exhibited specific transcriptional enrichment across chromosomes. Using the transcriptional signatures exhibited by distinct Leishmania stages during their development in the sand fly midgut, we determined the genes predominantly enriched in each stage, identifying multiple stage-specific markers for L. Infantum. Leading stage-specific marker candidates include genes encoding a zinc transporter in procyclics, a beta-fructofuranidase in nectomonads, a surface antigen-like protein in leptomonads, and an amastin-like surface protein in metacyclics. Overall, these findings demonstrate the transcriptional plasticity of the Leishmania parasite inside the sand fly vector and provide a repertoire of stage-specific markers for further development as molecular tools for epidemiological studies.

Prospection of immunological biomarkers for characterization and monitoring of asymptomatic Leishmania (Leishmania) infantum infection

Parasitology ◽  
2020 ◽  
Vol 147 (10) ◽  
pp. 1124-1132
Author(s):  
Gisele Macêdo Rodrigues da Cunha ◽  
Mariângela Carneiro ◽  
Marcelo Antônio Pascoal-Xavier ◽  
Iara Caixeta Marques da Rocha ◽  
Fernanda do Carmo Magalhães ◽  
...  
Keyword(s):  
Leishmania Infantum ◽  
Regression Tree ◽  
Cross Sectional Study ◽  
Asymptomatic Infection ◽  
Classification And Regression Tree ◽  
Soluble Antigen ◽  
Serum Samples ◽  
Serological Tests ◽  
Asymptomatic Group ◽  
Cross Sectional

AbstractIn areas endemic for Leishmania infantum, an asymptomatic infection may be an indicator of the extent of transmission. The main goal of this study was to evaluate the applicability of measuring circulating immunological biomarkers as an alternative strategy to characterize and monitor L. infantum asymptomatic infections in combination with serological methods. To this end, 179 children from a region endemic for visceral leishmaniasis (VL), aged 1–10 years old, selected from a cross-sectional study, were identified as asymptomatic (n = 81) or uninfected (n = 98) by qPCR and/or serological tests (ELISA using L. infantum soluble antigen and rK39), and, together with serum samples of children diagnosed with VL (n = 43), were subjected to avidity tests and cytokine levels measurement. Avidity rates (AR) ranging from 41 to 70% were found in 29 children (66%) from the asymptomatic group. On the other hand, high AR (above 70%) were observed in 27 children (64%) from the VL group. Logistic Regression and Classification and Regression Tree (CART) analyses demonstrated that lower AR and IFN-γ production associated with higher IL-17A levels were hallmarks in asymptomatic L. infantum infections. Therefore, this study proposes an association of immunological biomarkers that can be used as a complementary strategy for the characterization and monitoring of asymptomatic VL infections in children living in endemic areas.

scholarly journals Detection of Specific Antibodies against Toscana Virus among Blood Donors in Northeastern Italy and Correlation with Sand Fly Abundance in 2014

2020 ◽  
Vol 8 (2) ◽  
pp. 145 ◽  
Author(s):  
Silvia Morini ◽  
Mattia Calzolari ◽  
Giada Rossini ◽  
Nadia Pascarelli ◽  
Andrea Porcellini ◽  
...  
Keyword(s):  
Blood Donors ◽  
Strong Association ◽  
Immunofluorescence Assay ◽  
Sand Fly ◽  
Seroprevalence Rate ◽  
Toscana Virus ◽  
Serum Samples ◽  
Explanatory Variables ◽  
Northeastern Italy ◽  
Microneutralization Test

Toscana virus (TOSV) is a Phlebovirus transmitted by phlebotomine sand flies and is an important etiological agent of summer meningitis in the Mediterranean basin. Since TOSV infection is often asymptomatic, we evaluated the seroprevalence in blood donors (BDs) in the Bologna and Ferrara provinces (Northeastern Italy)—the areas with the highest and lowest numbers of TOSV neuroinvasive cases in the region, respectively. A total of 1208 serum samples from BDs were collected in April–June 2014 and evaluated for the presence of specific TOSV-IgG by ELISA. The IgG-reactive samples were confirmed by indirect immunofluorescence assay (IIF) and by microneutralization test (MN). Serum samples were defined as positive for anti-TOSV IgG when reactive by ELISA and by at least one second-level test; TOSV seroprevalence was 6.8% in the Bologna province, while no circulation of TOSV was detected in the Ferrara province. Sand fly abundance in 2014 was also estimated by a geographic information system using a generalized linear model applied to a series of explanatory variables. TOSV seroprevalence rate was strongly associated with the sand fly abundance index in each municipality, pointing out the strong association between sand fly abundance and human exposure to TOSV.

scholarly journals Impact of clinically acquired miltefosine resistance by Leishmania infantum on mouse and sand fly infection

2020 ◽  
Vol 13 ◽  
pp. 16-21 ◽  
Author(s):  
Lieselotte Van Bockstal ◽  
Dimitri Bulté ◽  
Sarah Hendrickx ◽  
Jovana Sadlova ◽  
Petr Volf ◽  
...  
Keyword(s):  
Leishmania Infantum ◽  
Sand Fly
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