Genetic characterization of Cryptosporidium in animal and human isolates from Jordan

Little is known about the epidemiology of Cryptosporidium in Jordan and to date, only one genotyping study has been conducted on Cryptosporidium isolates from Jordanian children. In the present study, a total of 284 faecal samples from Jordanian cattle, sheep, goats and chicken and 48 human faecal samples were screened for the presence of Cryptosporidium using an 18S quantitative PCR (qPCR) and a C. parvum/C. hominis specific qPCR at a lectin locus. Of these, 37 of 284 animal faecal samples were positive by qPCR at the 18S locus giving an overall prevalence of 11.6%. The point prevalence of Cryptosporidium in chickens, sheep, horses, cattle and goats ranged from 4.8% (chickens) to 18.7% (cattle). A total of six species were detected; C xiaoi (n = 9), C andersoni (n = 7), C ryanae (n = 5), C. parvum (n = 4), C baileyi (n =1) and a genetically distinct and potentially novel species in two isolates from horses. Sub-genotype analysis of the 4 C. parvum isolates at the 60-kDa glycoprotein (gp60) locus identified subtype IlaA19G2R1 (n=2) and IIaA16GR1 (n=2). For the human samples, 4 positives (8.3% prevalence) were detected. Of these, two were C. parvum (subtypes IldA20G1 and IIaA15G2R1) and two were C hominis (subtypes 1bA9G3 and 1bA10G2R2). Further studies are required to better understand the epidemiology and transmission of Cryptosporidium in Jordan

Modelling habitat suitability in Jordan for the cutaneous leishmaniasis vector (Phlebotomus papatasi) using multicriteria decision analysis

Cutaneous leishmaniasis (CL) is a zoonotic vector-borne neglected tropical disease transmitted by female Phlebotomine sand flies. It is distributed globally but a large proportion of cases (70–75%) are found in just ten countries. CL is endemic in Jordan yet there is a lack of robust entomological data and true reporting status is unknown. This study aimed to map habitat suitability of the main CL vector, Phlebotomus papatasi, in Jordan as a proxy for CL risk distribution to (i) identify areas potentially at risk of CL and (ii) estimate the human population at risk of CL. A literature review identified potential environmental determinants for P. papatasi occurrence including temperature, humidity, precipitation, vegetation, wind speed, presence of human households and presence of the fat sand rat. Each predictor variable was (a) mapped; (b) standardized to a common size, resolution and scale using fuzzy membership functions; (c) assigned a weight using the analytical hierarchy process (AHP); and (d) included within a multicriteria decision analysis (MCDA) model to produce monthly maps illustrating the predicted habitat suitability (between 0 and 1) for P. papatasi in Jordan. Suitability increased over the summer months and was generally highest in the north-western regions of the country and along the Jordan Valley, areas which largely coincided with highly populated parts of the country, including areas where Syrian refugee camps are located. Habitat suitability in Jordan for the main CL vector—P. papatasi—was heterogeneous over both space and time. Suitable areas for P. papatasi coincided with highly populated areas of Jordan which suggests that the targeted implementation of control and surveillance strategies in defined areas such as those with very high CL vector suitability (>0.9 suitability) would focus only on 3.42% of the country’s total geographic area, whilst still including a substantial proportion of the population at risk: estimates range from 72% (European Commission’s Global Human Settlement population grid) to 89% (Gridded Population of the World) depending on the human population density data used. Therefore, high impact public health interventions could be achieved within a reduced spatial target, thus maximizing the efficient use of resources

Phlebotomus papatasi SP15: mRNA expression variability and amino acid sequence polymorphisms of field populations

Citation: Ramalho-Ortigao, M., Coutinho-Abreu, I. V., Balbino, V. Q., Figueiredo, C. A. S., Mukbel, R., Dayem, H., . . . McDowell, M. A. (2015). Phlebotomus papatasi SP15: mRNA expression variability and amino acid sequence polymorphisms of field populations. Parasites & Vectors, 8, 14. doi:10.1186/s13071-015-0914-2Background: The Phlebotomus papatasi salivary protein PpSP15 was shown to protect mice against Leishmania major, suggesting that incorporation of salivary molecules in multi-component vaccines may be a viable strategy for anti-Leishmania vaccines. Methods: Here, we investigated PpSP15 predicted amino acid sequence variability and mRNA profile of P. papatasi field populations from the Middle East. In addition, predicted MHC class II T-cell epitopes were obtained and compared to areas of amino acid sequence variability within the secreted protein. Results: The analysis of PpSP15 expression from field populations revealed significant intra-and interpopulation variation.. In spite of the variability detected for P. papatasi populations, common epitopes for MHC class II binding are still present and may potentially be used to boost the response against Le. major infections. Conclusions: Conserved epitopes of PpSP15 could potentially be used in the development of a salivary gland antigen-based vaccine.Additional Authors: Lobo, N. F.;Mahon, A. R.;Emrich, S. J.;Kamhawi, S.;Collins, F. H.;McDowell, M. A

Antibody response to sand fly saliva is a marker of transmission intensity but not disease progression in dogs naturally infected with Leishmania infantum

BACKGROUND: Antibody responses to sand fly saliva have been suggested to be a useful marker of exposure to sand fly bites and Leishmania infection and a potential tool to monitor the effectiveness of entomological interventions. Exposure to sand fly bites before infection has also been suggested to modulate the severity of the infection. Here, we test these hypotheses by quantifying the anti-saliva IgG response in a cohort study of dogs exposed to natural infection with Leishmania infantum in Brazil. METHODS: IgG responses to crude salivary antigens of the sand fly Lutzomyia longipalpis were measured by ELISA in longitudinal serum samples from 47 previously unexposed sentinel dogs and 11 initially uninfected resident dogs for up to 2 years. Antibody responses were compared to the intensity of transmission, assessed by variation in the incidence of infection between seasons and between dogs. Antibody responses before patent infection were then compared with the severity of infection, assessed using tissue parasite loads and clinical symptoms. RESULTS: Previously unexposed dogs acquired anti-saliva antibody responses within 2 months, and the rate of acquisition increased with the intensity of seasonal transmission. Over the following 2 years, antibody responses varied with seasonal transmission and sand fly numbers, declining rapidly in periods of low transmission. Antibody responses varied greatly between dogs and correlated with the intensity of transmission experienced by individual dogs, measured by the number of days in the field before patent infection. After infection, anti-saliva antibody responses were positively correlated with anti-parasite antibody responses. However, there was no evidence that the degree of exposure to sand fly bites before infection affected the severity of the infection. CONCLUSIONS: Anti-saliva antibody responses are a marker of current transmission intensity in dogs exposed to natural infection with Leishmania infantum, but are not associated with the outcome of infection

ANIMAL MODELS FOR THE STUDY OF LEISHMANIASIS IMMUNOLOGY

Leishmaniasis remains a major public health problem worldwide and is classified as Category I by the TDR/WHO, mainly due to the absence of control. Many experimental models like rodents, dogs and monkeys have been developed, each with specific features, in order to characterize the immune response to Leishmania species, but none reproduces the pathology observed in human disease. Conflicting data may arise in part because different parasite strains or species are being examined, different tissue targets (mice footpad, ear, or base of tail) are being infected, and different numbers (“low” 1×102 and “high” 1×106) of metacyclic promastigotes have been inoculated. Recently, new approaches have been proposed to provide more meaningful data regarding the host response and pathogenesis that parallels human disease. The use of sand fly saliva and low numbers of parasites in experimental infections has led to mimic natural transmission and find new molecules and immune mechanisms which should be considered when designing vaccines and control strategies. Moreover, the use of wild rodents as experimental models has been proposed as a good alternative for studying the host-pathogen relationships and for testing candidate vaccines. To date, using natural reservoirs to study Leishmania infection has been challenging because immunologic reagents for use in wild rodents are lacking. This review discusses the principal immunological findings against Leishmania infection in different animal models highlighting the importance of using experimental conditions similar to natural transmission and reservoir species as experimental models to study the immunopathology of the disease

First genetic characterisation of Giardia in human isolates from Jordan

Little is known about the epidemiology of Giardia in Jordan and to date, no genotyping studies have been conducted on Giardia isolates from Jordanians. In the present study, a total of 49 microscopy-positive faecal samples from Jordanian patients suffering from giardiasis were analysed at two loci: the triose phosphate isomerase (tpi) gene and the glutamate dehydrogenase (gdh) gene. At the tpi locus, a total of 28 samples amplified and assemblage A was identified in 46.4 % (13/28) samples, while assemblage B was identified in 50 % (14/28) samples and a mixed assemblage A and B was identified in one sample (3.6 %) (Table 1). At the gdh locus 48 isolates amplified and of these assemblages A was identified in 43.7 % (21/48) of isolates and assemblage B in 56.3 % (27/48) of isolates. No mixed infections were detected at the gdh locus. Subtyping at the gdh locus identified sub-assemblage AII in 43.7 % (21/48) of isolates and sub-assemblages BIII and BIV in 25 % (12/48) and 31.2 % (15/48) of isolates, respectively, with more genetic diversity in AII isolates than BIII or BIV isolates. Novel sub-types within each sub-assemblage were identified suggesting unique endemicity and anthroponotic transmission of Giardia in Jordanian patients suffering from giardiasis. Further studies are required to better understand the epidemiology and transmission of Giardia in Jordan

Complement Receptor 3 Deficiency Influences Lesion Progression during Leishmania major Infection in BALB/c Mice▿

Leishmania major is an obligately intracellular protozoan parasite that causes cutaneous leishmaniasis. Like numerous intracellular pathogens, Leishmania exploits cell surface receptors as a means of entry into host cells. Complement receptor 3 (CR3; also called CD11b/CD18), a β2 integrin on phagocytic cells, is one such receptor. Ligation of CR3 has been shown to inhibit the production of interleukin-12, the cytokine that is pivotal in establishing the cell-mediated response necessary to combat intracellular infection. Here we investigate the role that CR3 plays in the establishment and progression of cutaneous leishmaniaisis in vivo. Dermal lesions of wild-type BALB/c mice are characteristically progressive and lead to extensive tissue necrosis coupled with elevated parasite burdens; CD11b-deficient BALB/c mice, however, demonstrate an intermediate phenotype characterized by chronic lesions and a reduced incidence of tissue damage. Infection followed by a reinfection challenge indicates that both susceptible (BALB/c) and resistant (C57BL/6) mice, regardless of CD11b status, develop resistance to L. major. In addition, CD11b does not bias the T helper cytokine response to L. major infection. Our results further indicate that CD11b is not necessary for disease resolution in resistant mice; rather, this protein appears to play a minor role in susceptibility