Phlebotomus papatasi (Scopoli), vector of zoonotic cutaneous leishmaniasis in Riyadh province, Saudi Arabia

Seroprevalence of Toscana and sandfly fever Sicilian viruses in humans and livestock animals from western Saudi Arabia

High seroprevalence rates of several phleboviruses have been reported in domestic animals and humans in sandfly-infested regions. Sandfly Fever Sicilian virus (SFSV) and Toscana virus (TOSV) are two of these viruses commonly transmitted by Phlebotomus sandflies. While SFSV can cause rapidly resolving mild febrile illness, TOSV could involve the central nervous system (CNS), causing diseases ranging from aseptic meningitis to meningoencephalitis. Sandfly-associated phleboviruses have not been investigated before in Saudi Arabia and are potential causes of infection given the prevalence of sandflies in the country. Here, we investigated the seroprevalence of SFSV and TOSV in the western region of Saudi Arabia in samples collected from blood donors, livestock animals, and animal handlers. An overall seroprevalence of 9.4% and 0.8% was found in humans for SFSV and TOSV, respectively. Seropositivity was significantly higher in non-Saudis compared to Saudis and increased significantly with age especially for SFSV. The highest seropositivity rate was among samples collected from animal handlers. Specifically, in blood donors, 6.4% and 0.7% tested positive for SFSV and TOSV nAbs, respectively. Animal handlers showed higher seroprevalence rates of 16% and 1% for anti-SFSV and anti-TOSV nAbs, respectively, suggesting that contact with livestock animals could be a risk factor. Indeed, sera from livestock animals showed seropositivity of 53.3% and 4.4% in cows, 27.5% and 7.8% in sheep, 2.2% and 0.0% in goats, and 10.0% and 2.3% in camels for SFSV and TOSV, respectively. Together, these results suggest that both SFSV and TOSV are circulating in the western region of Saudi Arabia in humans and livestock animals, albeit at different rates, and that age and contact with livestock animals could represent risk factors for infection with these viruses.

Molecular identification of Leishmania major species in phlebotomine sand flies from Al Ahsa, Eastern KSA

Objectives

Cutaneous leishmaniasis (CL) is considered an overlooked public health threat in KSA. CL is endemic to several Saudi regions, including Al Ahsa City, Eastern KSA. To our knowledge, no prior molecular identification of Leishmania parasites in vectors in Al Ahsa has been published. The aim of this study was to perform molecular identification of Leishmania species in sand flies collected from Al Ahsa.

Methods

This cross-sectional study was conducted in Al Ahsa from July 2020 to May 2021. Sand flies were collected from the three areas with the highest rates of CL cases and sand flies, according to data from the Vector Borne Diseases Prevention Center in Al Ahsa. CDC miniature light traps and sticky traps were used to collect sand flies. Pools of 3-10 female sand flies were subjected to genomic DNA extraction. The extracted DNA was then amplified with a protocol targeting the Leishmania genus and using species-specific primers. For Leishmania species identification, a PCR-restriction fragment length polymorphism (PCR-RFLP) method was used.

Results

Ten of 113 pools of samples tested positive for the Leishmania genus, according to our experimental protocol. Characterization of Leishmania species by PCR-RFLP established Leishmania major as the only species found in the collected sand flies.

Conclusion

This is the first documentation of molecular identification of Leishmania species in phlebotomine sand flies in the Al Ahsa region. L. major was the only species identified in our study. Further comprehensive research investigating the vectors and reservoirs will be crucial to establish the dynamics of transmission of Leishmania in Al Ahsa.

Cutaneous leishmaniasis in northwestern Saudi Arabia: identification of sand fly fauna and parasites

BACKGROUND

Cutaneous leishmaniasis (CL) is a vector-borne disease transmitted by the bite of an infected sand fly. This disease is highly prevalent in Saudi Arabia where Leishmania major and L. tropica are the etiological agents. In the region of Hail, northwestern of Saudi Arabia, the incidence is about 183 cases/year. However, the epidemiology of the disease in this area is not well understood. Thus, an epidemiological survey was conducted in 2015-2016 to identify the circulating parasite and the sand fly fauna in the region of Hail. Skin lesion scrapings were collected from suspected patients with CL.

METHODS

The diagnosis was made by microscopic examination of Giemsa-stained smear and PCR. The parasite was identified by PCR and sequencing of the single copy putative translation initiation factor alpha subunit gene. Sand fly specimens were collected and identified morphologically. Total DNA was extracted from the abdomen of female specimens and Leishmania DNA was detected by PCR.

RESULTS

Among the 57 examined patients, 37 were positive for CL. The identification of the parasite has revealed the single species Leishmania major. The 384 sand flies were collected belonged to two genera (Phlebotomus and Sergentomyia), six sub-genera and six species. Phlebotomus papatasi, Ph. kazeruni and Sergentomyia clydei were the dominant species. Leishmania DNA was detected in two females of Ph. papatasi two of Ph. kazeruni and one specimen of Sergentomyia clydei.

CONCLUSIONS

Leishmania major is confirmed to be the etiological agent of cutaneous leishmaniasis in northwestern Saudi Arabia. The molecular detection of Leishmania DNA in Ph. papatasi and Ph. kazeruni supports the potential role of these two species in the transmission of Leishmania. Further epidemiological studies are needed to prove their role and to evaluate the burden of CL in the study region.

Cutaneous and mucocutaneous leishmaniasis: Clinical perspectives

Leishmaniasis is endemic in 98 countries and territories, with 1.2 million new cases per year, making it a worldwide concern. The deadly visceral form is a leading cause of death from tropical parasitic infections, second only to malaria. Leishmaniasis appears to be increasing in many countries because of extended urbanization. The disease reservoir includes small mammals; parasite transmission occurs via bite of the female phlebotomine sandfly. Disease manifestations vary and largely depend upon the Leishmania species acquired. It may be first evident with a range of findings-from a localized cutaneous ulcer to diffuse painless dermal nodules-or, in the mucocutaneous form, ulceration of the oropharynx. In the potentially deadly visceral form, the internal organs and bone marrow are affected.

Bionomics of phlebotomine sand flies (Diptera: Psychodidae) in the province of Al-Baha, Saudi Arabia

The bionomics of phlebotomine sand flies (Diptera: Psychodidae) were studied for two successive years (January 1996-December 1997) at 12 collecting stations representing six sectors of the province of Al-Baha, Saudi Arabia. The predominant species was Phlebotomus bergeroti (41.7%), followed by lesser numbers of Phlebotomus sergenti (11%), Phlebotomus arabicus (10.6%), Sergentomyia tiberiadis (10.5%), Phlebotomus papatasi (10.2%), Sergentomyia antennata (9.6%), Phlebotomus alexandri (3%), Phlebotomus orientalis (2.3%) and Sergentomyia clydei (1.1%). The distribution of the collected species including species that are elsewhere known to act as vectors of human cutaneous leishmaniasis were distributed across different altitudes in Al-Baha. P. bergeroti, P. papatasi and P. arabicus were more abundant indoors; however, P. sergenti was more abundant outdoors. Sand fly populations exhibited three patterns of seasonal abundance in terms of their monthly activity. P. bergeroti, P. sergenti and P. arabicus were found to be naturally infected with Leishmania-like flagellates at an infection rate of 0.2%.

The biology and control of leishmaniasis vectors

Vector control remains a key component of many anti-leishmaniasis programs and probably will remain so until an effective vaccine becomes available. Technologies similar to those used for control of adult mosquitoes, specifically interior residual sprays and insecticide-treated nets, are currently at the forefront as disease control measures. This article provides a review of literature on the biology and control of sand fly vectors of leishmaniasis in the context of changing disease risks and the realities of modern vector control. The Literature Retrieval System of the Armed Forces Pest Management Board, Washington, DC, was the primary search engine used to review the literature.