A mathematical model of visceral leishmaniasis transmission and control: Impact of ITNs on VL prevention and elimination in the Indian subcontinent.

Visceral Leishmaniasis (VL) is a deadly, vector-borne, parasitic, neglected tropical disease, particularly prevalent on the Indian subcontinent. Sleeping under the long-lasting insecticide-treated nets (ITNs) was considered an effective VL prevention and control measures, until KalaNet, a large trial in Nepal and India, did not show enough supporting evidence. In this paper, we adapt a biologically accurate, yet relatively simple compartmental ordinary differential equations (ODE) model of VL transmission and explicitly model the use of ITNs and their role in VL prevention and elimination. We also include a game-theoretic analysis in order to determine an optimal use of ITNs from the individuals' perspective. In agreement with the previous more detailed and complex model, we show that the ITNs coverage amongst the susceptible population has to be unrealistically high (over 96%) in order for VL to be eliminated. However, we also show that if the whole population, including symptomatic and asymptomatic VL cases adopt about 90% ITN usage, then VL can be eliminated. Our model also suggests that ITN usage should be accompanied with other interventions such as vector control.

Seasonal dynamics, Leishmania diversity, and nanopore-based metabarcoding of blood meal origins in Culicoides spp. in the newly emerging focus of leishmaniasis in Northern Thailand.

BACKGROUND: Clinical cases of leishmaniasis caused by Leishmania (Mundinia) parasites have been increasingly reported in Southeast Asia, particularly Thailand. Recent evidence has shown that Leishmania (Mundinia) parasites successfully developed into infective metacyclic promastigotes in Culicoides biting midges, strongly supporting their putative role in disease transmission. However, Culicoides diversity, host preference, and Leishmania prevalence in endemic areas remain largely unknown. METHODS: We investigated the seasonal dynamics, infection prevalence, and blood meal identification of Culicoides collected from the emerging focus of visceral leishmaniasis in Lampang Province, Northern Thailand, during 2021-2023. Midge samples were molecularly screened for Leishmania using SSU rRNA-qPCR and ITS1-PCR, followed by Sanger plasmid sequencing, and parasite haplotype diversity was analyzed. Host blood meal origins were comparatively identified using host-specific Cytb-PCRs and a nanopore-based metabarcoding approach. RESULTS: A total of 501 parous and gravid females and 46 blood-engorged ones belonging to at least 17 species of five subgenera (Remmia, Trithecoides, Avaritia, Hoffmania, and Meijerehelea) and two species groups (Shortti and Calvipalpis) were collected with temporal differences in abundance. Leishmania was detected by SSU rRNA-qPCR in 31 samples of at least 11 midge species, consisting of Culicoides oxystoma, C. guttifer, C. orientalis, C. mahasarakhamense, C (Trithecoides) spp., C. innoxius, C. shortti, C. arakawae, C. sumatrae, C. actoni, and C. fulvus, with the overall infection prevalence of 5.7%. The latter six species represent the new records as putative leishmaniasis vectors in Northern Thailand. The ITS1-PCR and plasmid sequencing revealed that Leishmania martiniquensis was predominantly identified in all qPCR-positive species, whereas L. orientalis was identified only in three C. oxystoma samples. The most dominant haplotype of L. martiniquensis in Thailand was genetically intermixed with those from other geographical regions, confirming its globalization. Neutrality test statistics were also significantly negative on regional and country-wide scales, suggesting rapid population expansion or selective sweeps. Nanopore-based blood meal analysis revealed that most Culicoides species are mammalophilic, with peridomestic and wild mammals (cow, pig, deer, and goat-like species) and humans as hosts, while C. guttifer and C. mahasarakhamense fed preferentially on chickens. CONCLUSIONS: This study revealed seasonal dynamics and sympatric circulation of L. martiniquensis and L. orientalis in different species of Culicoides. Evidence of human blood feeding was also demonstrated, implicating Culicoides as putative vectors of human leishmaniasis in endemic areas. Further research is therefore urgently needed to develop vector control strategies and assess the infection status of their reservoir hosts to effectively minimize disease transmission.

Spatiotemporal relationship between agriculture, livestock, deforestation, and visceral leishmaniasis in Brazilian legal Amazon.

Visceral leishmaniasis (VL) is an urgent public health concern in Brazil. We evaluated the spatiotemporal distribution of VL to better understand the effects of economic activities related to agriculture, livestock, and deforestation on its incidence in the Brazilian Legal Amazon (BLA). The data on newly confirmed cases of VL in Brazilian municipalities from 2007 to 2020 were extracted from the Brazilian Notifiable Diseases Information System (SINAN) and analyzed. The data on agricultural production (planted area in hectares) and livestock (total number of cattle) were obtained from the Brazilian Institute of Geography and Statistics (IBGE), whereas deforestation data (in hectares) were obtained from the Amazon Deforestation Estimation Project (PRODES). SatScan and the local indicators of spatial association (LISA) were used to identify the spatial and temporal patterns of VL and its relationships with economic and environmental variables. The cumulative incidence rate was found to be 4.5 cases per 100,000 inhabitants. Based on the LISA results, areas with a high incidence of VL and deforestation were identified in the states of Roraima, Pará, and Maranhão. Strengthening deforestation monitoring programs and environmental enforcement actions can help implement public policies to control illegal deforestation and mitigate the socio-environmental vulnerability in the BLA. Therefore, areas identified in this study should be prioritized for controlling VL.

A case-control study on risk factors for visceral leishmaniasis in West Pokot County, Kenya.

BACKGROUND: Visceral leishmaniasis (VL) is a severe parasitic disease transmitted by phlebotomine sandflies. VL is endemic in West Pokot County, Kenya, where effective strategies to interrupt transmission are impeded by the limited understanding of VL risk factors. Therefore, this case-control study aimed to explore environmental, behavioural and household determinants of VL in West Pokot. METHODS: From November 2022 to January 2023, a structured questionnaire was administered to 36 symptomatic primary VL cases attending Kacheliba Sub-County Hospital in West Pokot and to 50 healthy controls from local villages. The VL status of all participants was confirmed using an rK39 rapid diagnostic test. Associations between questioned determinants and VL were investigated by means of age-corrected univariate logistic regression analysis. RESULTS: Significant associations were found between VL and housing characteristics, such as window presence and floor type. VL cases more frequently reported the presence of cattle, dogs and sheep in their house yards. VL was also associated with cutting down trees in the house yard and house proximity to several Acacia tree species. Furthermore, outdoor activities, including travelling outside the residence for more than 2 weeks, activities near termite mounds, and forest activities during the rainy season, increased the risk of VL. CONCLUSIONS: This work reports a number of previously undescribed risk factors for VL in the understudied West Pokot focus. The results suggest VL transmission occurs both peri-domestically at night and outdoors during the day, particularly when sandfly resting sites are disturbed. Our findings warrant further research into sandfly ecology and potential zoonotic parasite reservoirs in West Pokot.

A preliminary indication that HLA-A*03:01 may be associated with visceral leishmaniasis development in people living with HIV in Ethiopia.

Human immunodeficiency virus (HIV) co-infection is a major challenge for visceral leishmaniasis (VL) control, particularly in Ethiopia where the incidence of both pathogens is high. VL-HIV often leads to high rates of antileishmanial treatment failure and recurrent VL disease relapses. Considering the high prevalence of HIV and Leishmania in the Ethiopian population, preventing the progression of asymptomatic Leishmania infection to disease would be a valuable asset to VL disease control and to the clinical management of people living with HIV (PLWH). However, such a strategy requires good understanding of risk factors for VL development. In immunocompetent individuals living in Brazil, India, or Iran, the Human Leukocyte Antigen (HLA) gene region has been associated with VL development. We used NanoTYPE, an Oxford Nanopore Technologies sequencing-based HLA genotyping method, to detect associations between HLA genotype and VL development by comparing 78 PLWH with VL history and 46 PLWH that controlled a Leishmania infection, all living in a VL endemic region of North-West Ethiopia. We identified an association between HLA-A*03:01 and increased risk of VL development (OR = 3.89). These data provide candidate HLA alleles that can be further explored for inclusion in a potential Leishmania screen-and-treat strategy in VL endemic regions.

Cytokine profiles, blood parasite load and clinical features of visceral leishmaniasis in West Pokot County, Kenya.

Visceral leishmaniasis (VL) is a severe infectious disease caused by protozoan parasites of the Leishmania donovani complex. Blood cytokine concentrations in VL patients can inform us about underlying immunopathogenesis and may serve as a biomarker for treatment effectiveness. However, cytokine levels have not yet been studied in VL patients from Kenya, where case load is high. This study measured the serum cytokine profile, blood parasite load and clinical and haematological features of VL patients from West Pokot County, Kenya, over the course of treatment with sodium stibogluconate and paromomycin (SSG-PM). VL patients recruited at the hospital presented with splenomegaly and weight loss, and frequently had pancytopenia and anaemia. Median Leishmania parasite load in blood, determined with real-time polymerase chain reaction, was 2.6 × 104 parasite equivalents mL−1. Compared to endemic healthy controls, serum interferon gamma (IFN-γ), interleukin 5 (IL-5), IL-6, IL-10, IL-12p70, IL-17A and IL-27 were significantly elevated in untreated VL patients. Severe VL was associated with higher IL-10 and lower IFN-γ levels. After 17 daily injections with SSG-PM, disease symptoms disappeared, leukocyte and thrombocyte counts significantly increased, and blood parasite load decreased to undetectable levels in all VL patients. There was a significant decrease in IL-10 and IL-6, whereas IL-17A levels increased; the remaining cytokines showed no significant concentration change during treatment. In conclusion, the results suggest that SSG-PM treatment of VL patients from West Pokot was effective. Moreover, both inflammatory and regulatory immune responses appeared to decrease during treatment, although the increase in IL-17A could reflect a partial continuation of immune activation.

[Epidemiological characteristics of visceral leishmaniasis in Gansu Province from 2017 to 2023].

OBJECTIVE: To analyze the epidemiological characteristics of visceral leishmaniasis in Gansu Province from 2017 to 2023, so as to provide insights into formulation of the visceral leishmaniasis control strategy in the province. METHODS: All epidemiological features of confirmed and clinically diagnosed cases of visceral leishmaniasis reported in Gansu Province from January 1, 2017 to December 31, 2023 were retrieved from the Chinese Disease Prevention and Control Information System, and the epidemiological characteristics of visceral leishmaniasis cases were analyzed descriptively. RESULTS: A total of 280 visceral leishmaniasis cases were reported in 39 counties (cities and districts) of Gansu Province from 2017 to 2023, including 258 local cases reported in 21 endemic counties (districts) and 22 imported cases reported in 18 non-endemic areas. Of the 280 cases, there were 262 cases with mountain type zoonotic visceral leishmaniasis (MT-ZVL), 12 cases with desert-type zoonotic visceral leishmaniasis (DT-ZVL), and 6 cases with unknown type. Re-emerging MT-ZVL occurred in Maiji District, Qinzhou District, Lixian County, Kangxian County, Zhenyuan County, Qin'an County and Yongjing County, and re-emerging DT-ZVL occurred in Dunhuang City, while emerging DT-ZVL occurred in Yumen City. The five counties (districts) reporting the highest number of visceral leishmaniasis cases included Wudu District, Wenxian County, Tanchang County, Zhouqu County and Diebu County, and a total of 220 cases were reported in these five counties, accounting for 78.57% of all visceral leishmaniasis cases in the province. Visceral leishmaniasis cases were reported each month throughout the year, with the peak in July. All reported visceral leishmaniasis cases had ages of 6 months to 81 years, including 50.71% (142/280) under 15 years of age, 49.29% (138/280) at ages of 15 years and older, and of all cases under 15 years of age, children at ages of 0 to 3 years were the most commonly affected (27.14%, 76/280). Among 280 visceral leishmaniasis cases, there were 173 males and 107 females with a male to female ratio of 1.62∶1, and farmer was the most common occupation (40.36%), followed by diaspora children (37.86%). CONCLUSIONS: The prevalence of visceral leishmaniasis appeared an overall tendency towards a decline in Gansu Province from 2017 to 2023; however, there are still multiple challenges for visceral leishmaniasis control in the province. Reinforced dog monitoring and management, intensified human health education and improved capability building among professionals are recommended to manage the rebounding and spread of visceral leishmaniasis.

[Optimization of the control strategy and research priorities to combat the resurgence of visceral leishmaniasis in China].

Leishmaniasis is a zoonotic parasitic disease caused by Leishmania infection and transmitted by sandflies. There are three main forms of leishmaniasis, including cutaneous leishmaniasis, visceral leishmaniasis and mucocutaneous leishmaniasis. China is mainly endemic for visceral leishmaniasis, which is a class C notifiable infectious disease in the country. Following concerted efforts, the transmission of visceral leishmaniasis had been controlled in most endemic foci of China by the end of 1958, with a few cases reported in western China. Due to global climate changes and population mobility, resurgence of visceral leishmaniasis has recently occurred in historical endemic areas of central and western China, which is characterized by gradual expansion of endemic areas and remarkable rebounding epidemics. Hereby, we summarize the national and global epidemiology and control strategy of visceral leishmaniasis, propose 8 key research areas and 12 key research topics for visceral leishmaniasis control, and recommend the establishment of the joint prevention and control mechanism of "human-animals-vectors" and the working mechanism of animal prevention for human diseases based on the One Health approach, so as to combat the resurgence of visceral leishmaniasis in China.

[Distribution and seasonal fluctuation of visceral leishmaniasis vectors sandflies in Henan Province in 2023].

OBJECTIVE: To investigate the geographical distribution and seasonal fluctuations of visceral leishmaniasis vectors sandflies in Henan Province in 2023, so as to provide insights into the prevention and control of visceral leishmaniasis vectors. METHODS: A total of 23 counties (districts) were sampled from 18 cities of Henan Province from May to September, 2023 as sandfly surveillance sites, and sandflies were captured using human capture and light trapping methods. Following morphological identification, the changes in the sandfly density were calculated at different months and in different breeding habitats. RESULTS: A total of 406 light traps were set at sandfly surveillance sites in Henan Province from May to September, 2023, and a total of 3 137 female sandlies were captured, with an average density of 7.73 sandlies/(light·night). A total of 1 494 Phlebotomus chinensis sandflies were captured, including 1 222 female sandflies, with an average density of 3.01 sandflies/(light·night), and the highest density of P. chinensis was found in Gongyi City [17.00 sandflies/(light·night)]. A total of 5 544 sandflies were captured using the human capture method, including 230 P. chinensis, and the density of P. chinensis appeared a unimodal distribution, with a peak in early July [5.81 sandflies/(light·night)]. Among different breeding habitats, the highest P. chinensis density was detected in pigpens [4.50 sandflies/(light·night)]. CONCLUSIONS: P. chinensis was predominantly distributed in hilly areas of northern and central-western Henan Province in 2023, and the sandfly density appeared a unimodal distribution. Intensified monitoring of visceral leishmaniasis vectors is recommended.

[Spatiotemporal clustering and hot spot analysis of visceral leishmaniasis in Gansu Province from 1993 to 2023].

OBJECTIVE: To investigate the spatiotemporal clustering characteristics of the reported incidence of visceral leishmaniasis (VL) in Gansu Province from 1993 to 2023, so as to provide insights into the containment of VL and prevention of VL recurrence. METHODS: County (district)-level epidemical data of VL in Gansu Province from 1993 to 2023 were collected, and the geographical information database of reported VL incidence in Gansu Province was created according to the county-level administrative code and electronic maps in Gansu Province. In addition, the spatial autocorrelation analysis and hot spot analysis of the reported VL incidence were performed in Gansu Province using the software ArcGIS 10.8. RESULTS: A total of 2 597 VL cases were reported in Gansu Province from 1993 to 2023, with an annual average incidence rate of 3.036/105. Spatial autocorrelation analysis showed spatial clustering of the reported VL incidence in Gansu Province (Moran's I = 0.605, Z = 5.240, P < 0.001), appearing high-high clustering features (Getis-Ord G = 0.080, Z = 4.137, P < 0.001), and high-high clustering of the reported incidence of VL was identified in Diebu County, Tanchang County, Zhouqu County and Wenxian County. Hot spot analysis showed hot-spot areas of the reported VL incidence in Tanchang County, Zhouqu County, Wudu District and Wenxian County along the Bailong River basins and cold-spot areas in Qin'an County and Gangu County. CONCLUSIONS: There was spatial clustering and hot spots of the reported VL incidence in Gansu Province from 1993 to 2023. Intensified surveillance and control is required to prevent the spread of VL.

[Distribution and seasonal fluctuation of visceral leishmaniasis vectors sandflie in Lüliang City of Shanxi Province in 2023].

OBJECTIVE: To investigate the distribution and seasonal fluctuations of visceral leishmaniasis vectors sandflies in Lüliang City, Shanxi Province, so as to provide insights into assessment of the visceral leishmaniasis transmission risk and formulation of visceral leishmaniasis control measures. METHODS: A total of 12 natural villages were sampled from Shilou County, Lishi District, Lanxian County, Linxian County and Wenshui County in Lüliang City, Shanxi Province from June to September, 2023, and sandflies were captured using light traps from 7 breeding habitats, including farmers' houses, sheep pens, cattle pens, chicken coops, pig pens, mule and horse pens, and loess-cave dwellings. Following morphological identification of the sandfly species, the distribution of sandflies and the seasonal fluctuations of the sandfly density were analyzed. In addition, the Leishmania was detected in sandflies using a real-time fluorescence quantitative PCR assay. RESULTS: A total of 2 831 sandflies were captured with 156 light traps in Lüliang City from June to September, 2023, including 2 638 female sandflies (93.18%) and 193 male sandflies (6.82%), and the average density was 16.91 sandflies/(light-night). The seasonal fluctuations of the sandfly density all appeared a unimodal distribution in all survey sites, and the sandfly density peaked in July and then declined rapidly. Among all types of breeding habitats, the greatest sandfly density was found in sheep pens [39.04 sandflies/(light-night)]. In addition, 4.08% (2/49) of the sandfly samples were tested positive for Leishmania nucleic acid as revealed by the real-time fluorescence quantitative PCR assay. CONCLUSIONS: Sandflies were widely distributed in Lüliang City, Shanxi Province in 2023, and the peak of the sandfly density was observed in July, which had a visceral leishmaniasis transmission risk. Intensified surveillance of visceral leishmaniasis and sandfly vectors is required and targeted vector control is recommended.

[Epidemiological features of visceral leishmaniasis cases in Henan Province from 2021 to 2023].

OBJECTIVE: To analyze the characteristics of visceral leishmaniasis cases in Henan Province, so as to provide insights into formulation of the visceral leishmaniasis control srtrategy. METHODS: All epidemiological data of reported visceral leishmaniasis cases in Henan Province from 2021 to 2023 were retrieved from the National Notifiable Disease Report Information Management System of Chinese Center for Disease Control and Prevention, and the epidemiological features and diagnosis of visceral leishmaniasis cases were descriptively analyzed. RESULTS: A total of 93 visceral leishmaniasis cases were reported in Henan Province from 2021 to 2023, with a male to female ratio of 2.58∶1, and including 2 imported cases from other provinces and 91 local cases. The number of visceral leishmaniasis cases peaked during the period between March and May, and between July and October. The reported visceral leishmaniasis cases had ages of 7 months to 74 years, with the largest number of cases found at ages of 0 to 9 years (26 cases, 27.96%), followed by at ages of 60 to 70 years (24 cases, 25.81%). Farmer (47 cases, 50.54%) and diaspora children (19 cases, 20.43%) were predominant occupations, and 91 local visceral leishmaniasis cases were found in 6 cities of Zhengzhou, Luoyang, Anyang, Hebi, Sanmenxia and Xuchang. The median duration from onset of visceral leishmaniasis to diagnosis was 20 days, and there were 25.81% (24/93) cases with 10 days and less duration from onset to diagnosis, 38.71% (36/93) cases receiving diagnosis at 11 to 30 days following onset, and 35.48% (33/93) cases receiving diagnosis for more than 30 days following onset. All cases were predominantly diagnosed in province- (60.00%) and city-level (28.89%) medical institutions. CONCLUSIONS: The number of visceral leishmaniasis is on the rise in Henan Province, with a gradually expanding coverage. Intensified monitoring of visceral leishmaniasis cases, dogs, and vectors, dog management, sandflies control and improved individual protection are recommended to prevent the spread of visceral leishmaniasis.

[Epidemiological characteristics of local visceral leishmaniasis in Beijing Municipality from 2021 to 2023].

OBJECTIVE: To investigate the epidemiological characteristics of local visceral leishmaniasis in Beijing Municipality from 2021 to 2023, so as to provide insights into formulation of the visceral leishmaniasis control strategy. METHODS: Epidemiological data of visceral leishmaniasis cases reported in Beijing Municipality from 2021 to 2023 were collected from the National Health Informatization Disease Prevention and Control Information System, and the epidemiological characteristics of local visceral leishmaniasis cases were analyzed using a descriptive epidemiological method. In November 2021 and 2023, 50 to 100 permanent residents were voluntarily selected within a 100 meter radius of sites where patients lived or acquired Leishmania infections, and venous blood was sampled for anti-Leishmania antibody testing. Venous blood was sampled from dogs for anti-Leishmania antibody testing in natural villages where patients lived or acquired Leishmania infections, or in districts where Leishmania infected dogs were reported. In addition, sandflies were captured with CO2 mosquito traps and fine mesh nets in natural villages where patients lived or acquired Leishmania infections from May to September, 2021 and 2023, for sandfly species identification. RESULTS: A total of 4 local visceral leishmaniasis cases were reported in Beijing Municipality from 2021 to 2023, with ages of 2 to 77 years, and acquiring Leishmania infections in Mentougou District (2 cases), Changping District (1 case), and Yanqing District (1 case). The anti-Leishmania antibody testing was all negative in 73 human blood samples and the sero-prevalence of anti-Leishmania antibody was 25.00% in 36 venous blood samples from domestic dogs in 2021, with a total of 4 520 Phlebotomus chinensis captured. The sero-prevalence of anti-Leishmania antibody was 0.51% in 198 human blood samples and 13.58% in 243 venous blood samples from domestic dogs in 2023, with 16.10%, 25.00%, 17.78% and 3.13% sero-prevalence in dogs sampled from Mentougou District, Changping District, Yanqing District and Haidian District, respectively (P = 0.011), while a total of 1 712 Ph. chinensis were captured, including 1 421 female sandflies (86.54%). CONCLUSIONS: The prevalence of local visceral leishmaniasis was low in Beijing Municipality from 2021 to 2023; however, there is a risk of further spread in the epidemic foci. Intensified visceral leishmaniasis surveillance and control is recommended.

[Prevalence of canine Leishmania infections in Xin'an County, Luoyang City in 2020].

OBJECTIVE: To investigate the prevalence of canine Leishmania infections in villages endemic for visceral leishmaniasis in Xin'an County, Luoyang City, so as to provide insights into visceral leishmaniasis prevention and control. METHODS: All dogs were captured from Huzhanggou Village, Xin'an County, Luoyang City in August 2020, where local cases with visceral leishmaniasis lived. The basic characteristics of dogs were collected, and venous blood was collected via the ear or neck veins of dogs. The serum anti-Leishmania antibody was detected using the rk39 immunochromatographic test and Leishmania nucleic acid was detected using PCR assay, and the prevalence of Leishmania infection was estimated in dogs. RESULTS: A total of 133 domestic dogs were captured from Huzhanggou Village, with a median age of 18.0 (28.5) months. The sero-prevalence of anti-Leishmania antibody was 24.81% (33/133) and the prevalence of a positive PCR assay was 14.29% (19/133) in dogs. The median ages of Leishmania-infected and uninfected dogs were 24.0 (36.0) months and 12.0 (18.0) months, respectively (U = 872.000, P = 0.000), and the prevalence of Leishmania infection was 55.56% (5/9) in "mangy dogs" and 24.19% (30/124) in asymptomatic dogs (χ2 = 2.793, P = 0.095). CONCLUSIONS: There are a large number of asymptomatic dogs with Leishmania infections in Xin'an County, Luoyang City, with a high transmission risk of visceral leishmaniasis. Timely prevention and control measures are required to control the spread of visceral leishmaniasis.

[Risk factors of visceral leishmaniasis in the world: a review].

Visceral leishmaniasis is a zoonotic parasitic disease caused by viscerotropic Leishmania species and transmitted by bites of infected phlebotomine sandflies, which is predominantly prevalent in the Indian subcontinent, eastern Africa and South America. Currently, visceral leishmaniasis is the second most fatal parasitic disease in the world. Because of climate changes, urban development and individual conditions, there are changes in the density of visceral leishmaniasis vector sandflies and the likelihood of contact with humans, resulting in a visceral leishmaniasis transmission risk. The review summarizes natural, social and biological factors affecting the transmission of visceral leishmaniasis, so as to provide insights into formulation of targeted control measures for visceral leishmaniasis.

Feline leishmaniosis in the Mediterranean Basin: a multicenter study.

BACKGROUND: Cats are now recognized as competent hosts for Leishmania infantum and a blood source for sand fly vectors. Although canine leishmaniosis (CanL) is endemic in Mediterranean Basin countries, large-scale epidemiological studies are lacking for feline leishmaniosis (FeL). This study aimed to assess the prevalence of L. infantum infections, associated risk factors, clinical signs, and clinicopathological abnormalities in domestic cat populations from six Mediterranean Basin countries. METHODS: From 2019 to 2022, blood and serum samples of cats (n = 2067) living in Italy (n = 300), Greece (n = 297), Portugal (n = 295), France (n = 231), Israel (n = 313), and Spain (n = 631) were collected along with animal data (i.e., age, sex, breed, housing conditions, and geographical origin), clinical signs, and laboratory blood test parameters. Cats were grouped according to their age as kittens (up to 1 year), young (older than 1 and younger than 7 years), mature (between 7 and 10 years), and senior (older than 10 years). Serum samples were tested for L. infantum by immunofluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA), and blood samples of seropositive cats were tested for L. infantum kinetoplast deoxyribonucleic acid (kDNA). Viral infection by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) was molecularly addressed in all cats enrolled. Statistical analysis was performed to evaluate the association between the risk of L. infantum infection and independent variables, and among co-infection of L. infantum with FIV and/or FeLV, clinical signs, and clinicopathological abnormalities. RESULTS: Overall, 17.3% (358/2067) of cats scored positive for L. infantum by serological tests. Specifically, 24.7% were from Portugal, 23.2% from Greece, 16.6% from Israel, 15% from Spain, 13.3% from France, and 12.6% from Italy. Leishmania infantum DNA was detected in 15 seropositive animals. Housing condition and FIV infection proved to be risk factors for FeL. Leishmania seropositivity was significantly associated with weight loss, lymphadenomegaly, gingivostomatitis, and oral ulcers, as well as with reduced albumin and albumin/globulin ratio, increased total globulins and total proteins, leukocytosis, and thrombocytosis. CONCLUSIONS: This study provides, for the first time, a large-scale epidemiological survey on FeL and its clinical presentation, revealing that L. infantum circulates among domestic cats, especially shelter/free-roaming and FIV-infected animals, living in CanL endemic countries of the Mediterranean Basin.

Sero-Prevalence of Visceral Leishmaniasis and Associated Risk Factors among Febrile Patients Attending Metema Hospital, West Gondar Zone, North West Ethiopia.

INTRODUCTION: In Ethiopia, visceral leishmaniasis (VL) is a public health concern that has been spreading to new endemic foci in recent years. An estimated 3.2 million people are at risk of infection, with 3700-7400 new cases yearly. Thus, the study aimed to determine the prevalence of VL and associated risk factors among febrile patients attending Metema Hospital, North West Ethiopia. METHODS: A hospital-based cross-sectional study was conducted on 404 febrile patients attending Metema Hospital from February 2021 to June 2021. The test for VL was done using an immune-chromatographic test (RK39) according to the manufacturer's instructions (InBios International Inc., USA). An interviewer-administered, pretested questionnaire was used to collect data on risk factors associated with VL. Logistic regression and Chi-square assessed the association between VL and the associated risk factors. REULTS: The overall prevalence of visceral leishmaniasis was 18.8% (76/404), with a higher prevalence of VL in males, in the age category between 21 and 30, in study participants who completed elementary school, and in those who earned less than 500 birr monthly compared to their counterparts. Houses with thatched roofs (adjusted odd ratio (AOR) = 17.648, 95CI = 6.549,47.563), houses with mud walls (AOR = 2.538, 95% CI = 1.187-5.411), cattle ownership (AOR = 3.173, 95% CI = 1.286-7.826), dog ownership (AOR = 2,533, 95% CI = 1.256-5.111), presence of Acacia trees near houses (AOR = 1.975, 95% CI:1.004-3.886), presence of Balanites tree (AOR = 3.015, 95% CI = 1.610-5.992), and outdoor sleeping (AOR = 2.259, 95% CI: 1.107-14.607) were the predictors of VL in the present study. CONCLUSIONS: In the study area, VL is still very common. Thus, preventing and controlling infection in the area is largely dependent on raising community awareness of VL prevention and control measures and implementing the necessary interventions on the determinants that have been identified.

The Elimination Status of Visceral Leishmaniasis in Southeast Asia Region.

PURPOSE: Visceral leishmaniasis (VL) is caused by an intracellular parasite that is transmitted to humans by sandfly bites. It is prevalent throughout Asia, Africa, the Americas, and the Mediterranean area, where 147 million people are at risk of contracting the illness. The manifestation of heterotrophic illness relies on both Leishmania implicated and the host's immunological response, ranging from asymptomatic to severe leishmaniasis with potentially lethal effects. METHOD: We reviewed the literature (published till 31st December 2023) on the worldwide situation of leishmaniasis, standard and novel detection techniques, and traditional and modern treatment strategies and endeavors to eliminate VL. Moreover, epidemiological data was collected from the World Health Organization's publicly available databases. GraphPad Prism Version 8 was used to analyze and produce figures based on the epidemiological data. RESULTS: Diagnosis of parasites in tissues or serology is commonly employed. Diagnosis by identifying parasite DNA using molecular techniques is becoming more popular. Despite recent findings of L. donovani resistance to pentavalent antimoniate medications, it continues to be the cornerstone in the medical management of VL. Amphotericin B and its lipid formulations, injectable paromomycin, and oral miltefosine are among the new therapy options being researched. The number of reported VL cases has reduced remarkably over the last decade due to human interventions made to eliminate VL. Particularly countries from the South East Asian region have experienced momentous progress in reducing VL cases and eliminating this disease from this region. Owing to the robust elimination programs, countries such as Bangladesh has eliminated VL as a public health concern. India and Nepal are on the verge of its elimination. CONCLUSION: Rapid diagnosis, effective and inexpensive treatment, simple access to newly discovered medications, appropriate vector control, and a well-designed vaccine are all required for the elimination of this disease burden in impoverished areas of the globe.

First Molecular Evidence of Leishmania Infantum in Domestic Cats and Associated Risk Factors from the Black Sea Region of Türkiye.

PURPOSE: The objectives of the present study are to determine the molecular prevalence of Leishmania spp. in the owned domestic cats in the Black Sea Region of Türkiye and analyze the associated risk factors in FeL. METHODS: Conjunctival swabs (CS), blood, demographic, and clinical data were collected from 150 owned cats brought to the Veterinary Teaching Hospital during 2020-2022. Leishmania kinetoplast DNA (kDNA) from CS was screened by TaqMan Real-Time PCR (qPCR) with the genus-specific primers and a probe. RESULTS: All qPCR positive products were also amplified and sequenced to identify Leishmania species by ITS1 primers. Molecular prevalence of L. infantum found as 12.6% (19/150) in the observed cats in the Black Sea Region of Türkiye. There was a significant difference (p < 0.05) between neutered and intact cats with regarding to L. infantum positivity. Intact cats found to be 0.368 times more prone to be L. infantum-positive (L+). Dermatological lesions were found the most common (26.3%) problems in the L + cats. The median leucocyte count was the only parameter that was found statistically (p < 0.05) lower in the L + group (6.60) than the negative group (L-) (8.96), when comparing the WBC, NEU/LYM, MONO/LYM, EOS/LYM and PLT/LYM values. CONCLUSION: This study presented the molecular occurrence of FeL in the Black Sea Region of Türkiye for the first time indicating that the carrier status of the cats makes them alternative reservoirs for possible zoonotic transmission of L. infantum in this zone.