Sero-epidemological survey on canine visceral leishmaniasis and the distribution of sandfly vectors in Northwestern Turkey: Prevention strategies for childhood visceral leishmaniasis
Visceral leishmaniasis (VL) caused by Leishmania infantum, is an endemic disease in Aegean and Mediterranean Regions among humans and dogs. In this study, a sero-epidemiological survey
for VL and cutaneous leishmaniasis (CL), which both are sporadically reported in the region, were carried out in the villages
of Eskisehir, Afyon, and Bilecik cities. The study was designed according to the location of the sporadic cases of VL and
CL, and blood samples of 111 dogs were randomly collected. Lymph node aspiration samples were taken from dogs that have popliteal
lymphadenopathy. Sand flies were also collected using CDC light traps in the several localities. The sera samples were screened
using IFAT, ELISA, rk39 ELISA and dip-stick tests for anti-Leishmania antibodies. A total of 15 (13.51 per cent) dogs out of 111 were found to be seropositive by at least one of the tests. The
seropositivity ratios among dogs were found to be 27.5 per cent (8/29), 9.09 per cent (4/44) and 7.8 per cent (3/38) in Afyon,
Bilecik and Eskisehir cities respectively. Leishmania amastigotes were detected in 4 of the 14 lymph node aspiration samples (eight seronegative, six seropositive), and all of
them were seropositive dogs. One year later, two of the dogs were found to be dead and the other two were severely ill. Among
the 179 collected Phlebotomus specimens from, Phlebotomus major was found to be abundant (35.7 per cent) and the other species were P. simici (28.5 per cent), P. similis (34.7 per cent) and P. alexandri (1.1 per cent). In the study area, canine VL is more spread than human VL. Because dogs are playing an important role for
VL in Mediterranean Basin, and development of appropriate control measures will be necessary for childhood VL.
Available from: Jan Votypka
- "In addition, the actual number of members of the " major group " and their taxonomic status in Turkey is still unclear. In spite of the fact that the species status of P. syriacus has already been confirmed and P. major is believed to be an Indian species, P. major syriacus (Daldal et al., 1998) and P. major (Dogan et al., 2006) were still recorded as probable vector species in surveys concerning human and canine leishmaniasis in different parts of Turkey. Together with these inconsistent data, as seen in several vector species complexes, the difficulty of specific identification due to the blurriness of morphological characters further complicates an exact delineation of the distribution of " major group " members in Turkey. "
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ABSTRACT: The taxonomic status and distribution of the morphologically similar members of the Phlebotomus major complex in Turkey are unclear. To examine the utility of traditional morphological characters and molecular markers, sand flies were sampled from 90 localities in eleven different provinces covering a wide geographical range throughout Turkey. The morphometric variability was analyzed using multivariate analyses of twelve characters, while mitochondrial cytochrome b (Cyt b) and nuclear Elongation Factor 1α (EF 1-α) genes were used for molecular discrimination. Three distinct monophyletic lineages were identified based on the phylogenetic analysis of the combined data set of mitochondrial and nuclear gene regions, which were also supported by parsimony haplotype network analysis and AMOVA of Cyt b. The first lineage is restricted to south eastern Turkey and represents the species Phlebotomus syriacus, the second is present mostly in the westernmost and the easternmost localities and represents P. neglectus, and the third member of this complex is distributed across the mid-northern and mid-southern regions. None of the studied morphological characters were found to be sufficient to discriminate between these three members of the P. major s.l. complex; however their presence sympatrically in several localities supports their status as species rather than inter-population variability.
Available from: Francisco Morillas-Márquez
- "Conversely, in a study carried out by Reithinger et al. (2002) with dogs from an endemic area of Brazil, the specificity of the results obtained with methods based on protein rK39 was very low, whilst the sensitivity remained at the same levels as the reference technique (ELISA). Although at first this discrepancy in data may seem paradoxical, this has already been discussed in previous studies, with the possibility that these tests behave differently when they are applied in scenarios of differing epidemiological characteristics (Dogan et al. 2005; Otranto et al. 2004), with very similar results in human leishmaniasis (Chappuis et al. 2006; de-Assis et al. 2011). In a recent study performed by the WHO (2011), in which they compared a series of commercial diagnostic tests based on proteins rK39 (KD was among these) and rKE16 on patients with visceral leishmaniasis , the results indicate that the sensitivity and specificity of these tests were conditioned by the continent being studied, obtaining the lowest percentages in East Africa, followed by Brazil, and the highest on the Indian subcontinent, with values close to 100%. "
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ABSTRACT: Our aim was to establish the influence on the prevalence of canine leishmaniasis (CanL) of the following: (1) the use of different diagnostic techniques; (2) different positivity thresholds; (3) selection of animals either at random from a population or focused on symptomatic individuals, (4) the function which the dog performs; and (5) scenarios with differing epidemiological characteristic. Three groups of dogs were analysed (416 sampled at random from an endemic area, 71 with symptomatology compatible with CanL and 15 from a non-endemic area) using three serological techniques (indirect fluorescence antibody test (IFAT), Kalazar Detect(TM) and Q Letitest ELISA) and a PCR-ELISA. The diagnostic technique had a considerable influence on the CanL prevalence value obtained. Uncertain antibody titres were more representative in dogs sampled at random and with the IFAT technique. Although employing different capture antigens, correlation of results was higher between the two commercial techniques in the group of dogs with symptomatology compatible with CanL. The sensitivity and specificity values of the different diagnostic techniques were affected by the epidemiological characteristic of the area under study, the presence of clinical signs and the function which the dog performs. This must be taken into account when comparing endemicity in different geographical areas, such as in studies carried out for the construction of risk maps. Using more than one technique, and adopting the criterion of considering an animal to be positive only when it has been diagnosed as such by more than one technique, considerably raises the prevalence values but maintains the differences between areas with different characteristics.
Available from: Seray Töz (Özensoy)
- "Therefore, there are still more extensive surveys needed to determine the sand fly fauna there. The entomological surveys for leishmaniasis were mainly carried out in endemic areas (Dogan et al. 2006, Ertabaklar et al. 2005b, Ozensoy Toz et al. 2009), but there is limited information about the sand fly fauna in new foci, as in Aydin province. Cases of human and canine visceral leishmaniasis have been reported from Kusadasi, a town in Aydin province, in western Turkey, since 1993. "
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ABSTRACT: An entomological survey was conducted to determine the spatial distribution of phlebotomine fauna and understand the effect of environmental factors. The entomological survey was carried out during 2006-2007 in a study area in the rural area of Aydin province, near the Kusadasi town where VL, CL, and canine leishmaniasis (CanL) are endemic. In 2006 and 2007, 132 locations were sampled using sticky traps mainly on embankments. Detailed environmental and meteorological information was also collected for each location. The results of entomological studies indicated that the probable vectors are Phlebotomus tobbi and P. neglectus for VL and CanL, and P. similis for CL in this western leishmaniasis focus. The data revealed a correlation between their presence and spatial variables such as altitude, sampling site location, and humidity. The distribution areas of probable vector species in this study area allowed the identification of risk levels, which may provide useful information to guide the leishmaniasis research in endemic regions.
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