Livestock infected with Leishmania spp. in southern Iran

Epidemiological surveillance of Leishmania infantum in wild lagomorphs in Spanish Mediterranean ecosystems

Wild lagomorphs play a key epidemiological role as reservoirs of Leishmania infantum, causative agent of the largest outbreak of human leishmaniosis in Europe to date. A large-scale survey study was conducted on wild rabbit (Oryctolagus cuniculus) and Iberian hare (Lepus granatensis) populations in Spanish Mediterranean ecosystems to evaluate the exposure of L. infantum and investigate potential risk factors associated with exposure to this zoonotic parasite. Between 2018 and 2021, a total of 631 wild lagomorphs (471 wild rabbits and 160 Iberian hares) were collected in Andalusia (southern Spain) and tested for antibodies against L. infantum using the indirect fluorescent antibody test (IFAT). Spleen samples from 563 of the wild lagomorphs sampled (441 wild rabbits and 122 Iberian hares) were also evaluated by real-time quantitative PCR (qPCR) for detection of Leishmania kDNA. Exposure to L. infantum (positive by IFAT and/or qPCR) was detected in 56.4 % (356/631; 95 %CI: 52.3-60.3) of the lagomorphs analyzed. Anti-Leishmania antibodies were found in 12.8 % (81/631; 95 %CI: 10.2-15.5) of the animals, and L. infantum kDNA was detected in 59.0 % (332/563; 95 %CI: 54.9-63.0) of the spleen samples tested. Phylogenetic analysis revealed high homology (99.9-100 %) between L. infantum sequences obtained and strains previously isolated from humans in Spain. While apparent seroprevalence was significantly higher in Iberian hares (19.4 %; 95 %CI: 13.3-25.5) compared to wild rabbits (10.6 %; 95 %CI: 7.9-13.4), no significant differences in prevalence were found between wild rabbits (61.0 %; 95 %CI: 56.5-65.6) and Iberian hares (51.6 %; 95 %CI: 42.8-60.5). At least one positive animal was found on 64.8 % (70/108) of the hunting grounds sampled, and a high-risk spatial cluster (P < 0.001) was also identified in central Andalusia. The multivariable analysis identified bioclimatic level (meso-Mediterranean climate) and the presence of goats on hunting grounds as risk factors potentially associated with L. infantum exposure in wild lagomorphs. This study shows high, widespread exposure, but heterogeneous distribution of L. infantum in wild lagomorph populations in Mediterranean ecosystems in southern Spain. The results point to the need to promote integrated surveillance programs for the detection of Leishmania spp. in wild lagomorphs in order to establish effective control measures against human leishmaniosis under a One Health approach.

Presence of anti-Leishmania infantum antibodies in sheep (Ovis aries) in Spain

Sandflies are the primary transmission vector for Leishmania spp parasite in endemic regions. The role of other animals, different from the dog, is under discussion in the leishmaniosis endemic countries. A limited number of reports have been published on the possible role of livestock in European countries for Leishmania maintenance and diffusion. The aim of the present study was to perform a serosurvey on sheep in areas of Spain that are endemic for zoonotic leishmaniosis and establish the possible role of sheep regarding Leishmania infantum infection in endemic areas. Three hundred and two serum samples were obtained from sheep and were evaluated for serological survey to detect L. infantum by using the in-house ELISA technique. Twenty-eight out of the 302 samples included in this study, were positive for L. infantum antibodies (9.27%). In the present study, a significant association was found between adult age and seropositivity (p = 0.006) and female gender and seropositivity (p = 0.02). This association has not been previously described in other European studies related to L. infantum infection in sheep. Our study reveals that domestic sheep in a European Mediterranean country are exposed to L. infantum. To our knowledge, this study demonstrates the presence of seropositive sheep in different regions of Spain for the first time. Further epidemiological studies focus on evaluating the rural cycle of this parasite to know if livestock could act as a potential reservoir are needed.

Molecular identification of Leishmania tropica in mammals occurring in human-inhabited areas of a cutaneous leishmaniasis endemic focus in North-West Pakistan

Cutaneous Leishmaniasis is endemic in the tribal district of Khyber near the Pak-Afghan border and is caused by Leishmania tropica. In Pakistan, cutaneous leishmaniasis caused by L. tropica is considered anthroponotic and is thought to be maintained by a human-sand fly-human transmission cycle. Along with humans, other mammals may also be acting as reservoir hosts of leishmaniasis in the study area. To investigate the role of non-human mammals in the transmission of leishmaniasis, blood samples were collected from 245 animals from the CL endemic district of Khyber, Pakistan. Leishmania parasite in these samples was detected by amplifying the species-specific sequences in minicircle kinetoplast DNA, using PCR. L. tropica DNA was detected in 18 (7.35%) samples, comprising 11 cows (Bos taurus), 6 goats (Capra hircus), and 1 dog (Canus lupus familiaris). Only a single cow and dog had a leishmaniasis-like lesion, and the remaining positive samples were asymptomatic. None of the tested sheep (Ovis aries) and rat (Rattus rattus, Rattus norvegicus) was positive. The present study reports the first instance of molecular detection of L. tropica in domestic animals. Our study indicates that along with humans' cows, goats and dogs may also be playing an important role in the transmission of anthroponotic cutaneous leishmaniasis in district Khyber in particular and Pakistan in general.

A disfiguring neglected tropical disease sweeps war-torn Yemen: a community-based study of prevalence and risk factors of cutaneous leishmaniasis among rural communities in the western highlands

BACKGROUND

Cutaneous leishmaniasis (CL) is a major health problem in Yemen and is endemic in many rural areas across the country.

METHODS

A community-based cross-sectional survey followed by unmatched case-control comparisons was conducted among 612 participants in Utmah district, western Yemen. A total of 223 participants were included in the case-control analysis to identify the significant risk factors. Skin scrapping samples were examined by microscopy and internal transcribed spacer 1 nested polymerase chain reaction.

RESULTS

Overall, 33% (202/612) of the participants had active skin lesions and/or scars that met the clinical criteria for CL. A total of 90 (14.7%) participants had suspected active CL lesions; however, a prevalence of 8.7% (53/612) was obtained based on molecular and parasitological examination, with Leishmania tropica being the only causative agent identified. Multivariable logistic regression analyses showed that being ≤10 y old, being female, living in houses with cracked walls, living in the presence of other family members with typical ulcerating skin diseases and sleeping outside were factors significantly associated with an increased likelihood of having CL. Moreover, keeping livestock on the ground floor of the house was significantly associated with a decreased likelihood of having CL.

CONCLUSION

The study reveals an alarmingly high prevalence of CL among the studied population. Therefore there is an urgent need for effective control measures and improved treatment efforts against this devastating disease.

Is leishmaniasis the new emerging zoonosis in the world?

Leishmania is a genus of parasitic protozoa that causes a disease called leishmaniasis. Leishmaniasis is transmitted to humans through the bites of infected female sandflies. There are several different species of Leishmania that can cause various forms of the disease, and the symptoms can range from mild to severe, depending on species of Leishmania involved and the immune response of the host. Leishmania parasites have a variety of reservoirs, including humans, domestic animals, horses, rodents, wild animals, birds, and reptiles. Leishmaniasis is endemic of 90 countries, mainly in South American, East and West Africa, Mediterranean region, Indian subcontinent, and Central Asia. In recent years, cases have been detected in other countries, and it is already an infection present throughout the world. The increase in temperatures due to climate change makes it possible for sandflies to appear in countries with traditionally colder regions, and the easy movement of people and animals today, facilitate the appearance of Leishmania species in new countries. These data mean that leishmaniasis will probably become an emerging zoonosis and a public health problem in the coming years, which we must consider controlling it from a One Health point of view. This review summarizes the prevalence of Leishmania spp. around the world and the current knowledge regarding the animals that could be reservoirs of the parasite.