Spatial distribution of sand flies (Diptera: Psychodidae; Larroussius group), the vectors of visceral leishmaniasis in Northwest of Iran

Visceral Leishmaniasis (VL) is caused by protozoan of genus Leishmania and transmitted by sand flies of genus Lutzomyia, which has been adapted to the peridomicile environment where dogs are their mainly food source, increasing the risk for human cases. In this study, techniques of geoprocessing and spatial statistics were utilized as a contribution to understanding the epidemiological dynamics of VL in the urban area of Ilha Solteira, SP.

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Insecticide Susceptibility Status of Wild Population of Phlebotomus kandelakii and Phlebotomus perfiliewi transcaucasicus Collected from Visceral Leishmaniasis Endemic Foci in Northwestern Iran

Journal of Arthropod-Borne Diseases ◽

10.18502/jad.v14i3.4561 ◽

2020 ◽

Author(s):

Yavar Rassi ◽

Eslam Moradi-Asl ◽

Hassan Vatandoost ◽

Malek Abazari ◽

Abedin Saghafipour

Keyword(s):

Visceral Leishmaniasis ◽

Control Group ◽

Sand Flies ◽

Control Programs ◽

Lambda Cyhalothrin ◽

Northwestern Iran ◽

Northwest Of Iran ◽

Phlebotomus Perfiliewi ◽

Susceptibility Tests ◽

Susceptibility Status

Background: Phlebotomus kandelakii and Phlebotomus perfiliewi transcaucasicus sand flies are the vectors of visceral leishmaniasis in Iran. The aim of this study was to evaluate the susceptibility of Ph. kandelakii and Ph. perfiliewi transcaucasicus, collected from an endemic focus of visceral leishmaniasis (VL) in the northwest of Iran, to different selected insecticides. Methods: Sand flies were collected from the villages of Meshkinshahr and Germi Counties using light traps and aspirators from May to October 2019. The sand flies were identified as Ph. kandelakii and Ph. perfiliewi transcaucasicus using standard identification keys. Susceptibility test was carried out against DDT (4%), Malathion (5%), Propoxur (0.1%) and Lambda-cyhalothrin (0.05%) according to the WHO standard method. MedCalc statistical software was employed to calculate LT50 and LT90 and to compare the chances of sand flies surviving the exposure to the studied insecticides. Results: A total of 1,278 female specimens were used for the susceptibility tests. Out of which 1,063 samples were used for the test and 215 for the control group. The estimated LT50 values for DDT (4%), Malathion (5%), Propoxur (0.1%), and Lambda-cyhalothrin (0.05%) for Ph. kandelakii were 15.1, 13.4, 15.4 and 5.8 minutes respectively, and for Ph. perfiliewi transcaucasicus were 11.9, 15.6, 15.9 and 5.8 minutes respectively. Conclusion: This susceptibility studies revealed different LT50 values for different insecticides efficient against Ph. kandelakii and Ph. perfiliewi transcaucasicus. The regular monitoring for the resistance of Ph. kandelakii and Ph. perfiliewi transcaucasicus sand flies seems necessary in diseases control programs in this area.

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Species diversity and spatial distribution of CL/VL vectors: assessing bioclimatic effect on expression plasticity of genes possessing vaccine properties isolated from wild-collected sand flies in endemic areas of Iran

BMC Infectious Diseases ◽

10.1186/s12879-021-06129-0 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ali Bordbar ◽

Parviz Parvizi

Keyword(s):

Gene Expression ◽

Spatial Distribution ◽

Interpolation Method ◽

Diversity Index ◽

Fold Change ◽

Control Measures ◽

Pcr Analysis ◽

Physiological Status ◽

Sand Flies ◽

Risk Maps

Abstract Background Leishmaniasis is one of the ten most important neglected tropical diseases worldwide. Understanding the distribution of vectors of visceral and cutaneous leishmaniasis (VL/CL) is one of the significant strategic frameworks to control leishmaniasis. In this study, the extent of the bioclimatic variability was investigated to recognize a rigorous cartographic of the spatial distribution of VL/CL vectors as risk-maps using ArcGIS modeling system. Moreover, the effect of bioclimatic diversity on the fold change expression of genes possessing vaccine traits (SP15 and LeIF) was evaluated in each bioclimatic region using real-time PCR analysis. Methods The Inverse Distance Weighting interpolation method was used to obtain accurate geography map in closely-related distances. Bioclimatic indices were computed and vectors spatial distribution was analyzed in ArcGIS10.3.1 system. Species biodiversity was calculated based on Shannon diversity index using Rv.3.5.3. Expression fold change of SP15 and LeIF genes was evaluated using cDNA synthesis and RT-qPCR analysis. Results Frequency of Phlebotomus papatasi was predominant in plains areas of Mountainous bioclimate covering the CL hot spots. Mediterranean region was recognized as an important bioclimate harboring prevalent patterns of VL vectors. Semi-arid bioclimate was identified as a major contributing factor to up-regulate salivary-SP15 gene expression (P = 0.0050, P < 0.05). Also, Mediterranean bioclimate had considerable effect on up-regulation of Leishmania-LeIF gene in gravid and semi-gravid P. papatasi population (P = 0.0109, P < 0.05). Conclusions The diversity and spatial distribution of CL/VL vectors associated with bioclimatic regionalization obtained in our research provide epidemiological risk maps and establish more effectively control measures against leishmaniasis. Oscillations in gene expression indicate that each gene has its own features, which are profoundly affected by bioclimatic characteristics and physiological status of sand flies. Given the efficacy of species-specific antigens for vaccine production, it is essential to consider bioclimatic factors that have a fundamental role in affecting the regulatory regions of environmentally responsive loci for genes used in vaccine design.

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Sexual and vertical transmission of visceral leishmaniasis

The Journal of Infection in Developing Countries ◽

10.3855/jidc.4108 ◽

2014 ◽

Vol 8 (04) ◽

pp. 403-407 ◽

Cited By ~ 17

Author(s):

Andreia P Turchetti ◽

Tayse D Souza ◽

Tatiane A Paixão ◽

Renato L. Santos

Keyword(s):

Visceral Leishmaniasis ◽

Vertical Transmission ◽

Leishmania Infantum ◽

Vertebrate Host ◽

Domestic Dog ◽

Sand Flies ◽

Phlebotomine Sand Flies

Visceral leishmaniasis (VL) is an important zoonosis caused by Leishmania infantum, which has in the domestic dog its principal vertebrate host. VL is usually transmitted by phlebotomine sand flies, however atypical routes of transmission have been described. In this review we discuss the the role of sexual and vertical transmissions, and their role in the maintenance of VL in canine populations.

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Ecology of Lutzomyia longipalpis and Lutzomyia migonei in an endemic area for visceral leishmaniasis

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612014068 ◽

2014 ◽

Vol 23 (3) ◽

pp. 320-327 ◽

Cited By ~ 11

Author(s):

Rafaella Albuquerque Silva ◽

Fabricio Kassio Moura Santos ◽

Lindemberg Caranha de Sousa ◽

Elizabeth Ferreira Rangel ◽

Claudia Maria Leal Bevilaqua

Keyword(s):

Visceral Leishmaniasis ◽

Leishmania Infantum ◽

Indoor Environment ◽

Endemic Area ◽

Natural Infection ◽

Sampling Site ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Sampling Points ◽

Lutzomyia Migonei

The main vector for visceral leishmaniasis (VL) in Brazil is Lutzomyia longipalpis. However, the absence of L. longipalpis in a region of autochthonous VL demonstrates the participation of other species in the transmission of the parasite. Studies conducted in La Banda, Argentina, and São Vicente Férrer, Pernambuco State, Brazil, have correlated the absence of L. longipalpisand the presence of L. migonei with autochthonous cases of VL. In São Vicente Férrer, Pernambuco, there was evidence for the natural infection of L. migonei with Leishmania infantum chagasi. Thus, the objective of this work was to assess the ecology of the sand flies L. longipalpis and L. migonei in Fortaleza, an endemic area for VL. Insect capture was conducted at 22 sampling points distributed across four regions of Fortaleza. In total, 32,403 sand flies were captured; of these, 18,166 (56%) were identified as L. longipalpis and 14,237 (44%) as L. migonei. There were significant density differences found between the vectors at each sampling site (indoors and outdoors) (p <0.0001). These findings confirm that L. migonei and L. longipalpis are distributed throughout Fortaleza, where they have adapted to an indoor environment, and suggest that L. migonei may share the role as a vector with L. longipalpis in the transmission of VL in Fortaleza.

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Density of Sand Flies (Diptera: Psychodidae) in Domestic and Wild Animal Shelters in an Area of Visceral Leishmaniasis in the State of Rio Grande do Norte, Brazil

Memórias do Instituto Oswaldo Cruz ◽

10.1590/s0074-02761999000400001 ◽

1999 ◽

Vol 94 (4) ◽

pp. 427-432 ◽

Cited By ~ 32

Author(s):

Maria de Fátima Freire de Melo Ximenes ◽

Maria de Fátima de Souza ◽

Eloy Guilhermo Castellón

Keyword(s):

Visceral Leishmaniasis ◽

Rio Grande ◽

Wild Animal ◽

The State ◽

Sand Flies ◽

Animal Shelters

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Human and canine visceral leishmaniasis in an emerging focus in Araçuaí, Minas Gerais: spatial distribution and socio-environmental factors

Memórias do Instituto Oswaldo Cruz ◽

10.1590/0074-02760160133 ◽

2016 ◽

Vol 111 (8) ◽

pp. 505-511 ◽

Cited By ~ 16

Author(s):

Renata Luiz Ursine ◽

João Victor Leite Dias ◽

Harriman Aley Morais ◽

Herton Helder Rocha Pires

Keyword(s):

Spatial Distribution ◽

Visceral Leishmaniasis ◽

Environmental Factors ◽

Minas Gerais ◽

Canine Visceral Leishmaniasis

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Odour of domestic dogs infected with Leishmania infantum is attractive to female but not male sand flies: evidence for parasite manipulation

10.1101/2020.11.09.374207 ◽

2020 ◽

Author(s):

Monica E. Staniek ◽

James G.C. Hamilton

Keyword(s):

Visceral Leishmaniasis ◽

Leishmania Infantum ◽

Feeding Activity ◽

Blood Feeding ◽

Human Infection ◽

T Test ◽

Domestic Dogs ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Paired T Test

AbstractGlobally visceral leishmaniasis (VL) causes thousands of human deaths every year. In South America, the etiologic agent, Leishmania infantum, is transmitted from an infected canine reservoir to human hosts by the blood-feeding activity of the sand fly vector, predominantly, Lutzomyia longipalpis. Previous evidence from model rodent systems have suggested that the odour of infected hosts is altered by the parasite making them more attractive to the vector leading to an increased biting rate and improved transmission prospects for the pathogen. However, the effect of Le. infantum infection on the attractiveness of naturally infected dogs which are integral to human infection, has not been assessed.Hair collected from infected and uninfected dogs residing in a VL endemic city in Brazil. was entrained to collect the volatile chemical odours present in the headspace. Female and male Lu. longipalpis sand flies were offered a choice of infected or uninfected odour in a series of behavioural experiments. Control experiments established that female and male Lu. longipalpis were equally attracted to uninfected dog odour, female Lu. longipalpis were significantly more attracted to infected dog odour than uninfected dog odour in all 15 experimental replicates (average 45.7±0.87 females attracted to infected odour; 23.9±0.82 to uninfected odour; paired T-test, P=0.000). Male Lu. longipalpis did not significantly prefer either infected or uninfected odour (average 36.1±0.4 males to infected odour; 35.7±0.6 to uninfected odour; paired T-test, P=0.722). A significantly greater proportion of females chose the infected dog odour compared to the males (paired T-test, P=0.000).The results show that dogs infected with Le. infantum are significantly more attractive to blood-feeding female than male sand flies. This is strong evidence for parasite manipulation of the host odour in a natural transmission system and indicates that infected dogs may have a disproportionate significance in maintaining infection in canine and human infection.Author SummaryVisceral leishmaniasis (VL) is a disease caused by the Protist parasite Leishmania infantum. In Brazil and other South and Central American countries, the parasite is transmitted by the blood-feeding activity of infected female Lutzomyia longipalpis sand flies. The disease leads to thousands of human cases and deaths every year. Domestic dogs are the reservoir of infection for humans therefore understanding the effect of infection on dogs is important in developing an understanding of the epidemiology of the disease. Although previous studies on rodent models of Le. infantum infection have shown that infected Golden Hamsters are more attractive to Lu. longipalpis the attractiveness of naturally infected dogs to the insect vector has not been previously been investigated. In this study we showed that the odour of infected dogs is significantly more attractive to female sand flies which can transmit the pathogen than to male sand flies which do not. This clear-cut difference in attraction of female and males suggests that the females are preferentially attracted by parasite infected hosts and may lead to enhanced infection and transmission opportunities for the parasite.

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Entomological Studies in Itaúna, Brazil, an Area With Visceral Leishmaniasis Transmission: Fauna Survey, Natural Leishmania Infection, and Molecular Characterization of the Species Circulating in Phlebotomine Sand Flies (Diptera: Psychodidae)

Journal of Medical Entomology ◽

10.1093/jme/tjz061 ◽

2019 ◽

Vol 56 (5) ◽

pp. 1368-1376 ◽

Cited By ~ 4

Author(s):

Josiane V Lopes ◽

Erika M Michalsky ◽

Nathalia C L Pereira ◽

Adão J V de Paula ◽

Fabiana O Lara-Silva ◽

...

Keyword(s):

Visceral Leishmaniasis ◽

Natural Infection ◽

Local Population ◽

Influential Factor ◽

Sand Fly ◽

Health Concern ◽

Leishmania Infection ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Phlebotomine Sand Flies

Abstract Among neglected tropical diseases, visceral leishmaniasis (VL) shows great relevance in global terms and is a serious public health concern due to the possibility of severe and lethal forms in humans. In this study, we evaluate entomological factors such as diversity and abundance of phlebotomine sand flies (Diptera:Psychodidae) and the Leishmania species circulating in these species in possible association with VL transmission in the Brazilian town Itaúna. The entomological collections were performed during three consecutive nights, always in the third week of each month, within a period of 12 mo. A total of 1,786 sand fly specimens were collected, from which 20% were collected inside houses. The influence of three local climatic variables (temperature, rainfall, relative humidity) on the population sizes of these insects was evaluated. Temperature was the most influential factor, with a significant positive correlation with the local population size of phlebotomine sand flies collected per month. Lutzomyia longipalpis (Lutz & Neiva, 1912) was the predominant species in the study area. Leishmania DNA was detected in nine out of 133 pools of sand fly females, using nested/PCR, which resulted in a minimal natural infection rate of 2.91%. DNA from Leishmania infantum Nicolle, 1908 (Kinetoplastida: Trypanosomatida), was detected in Evandromyia cortelezzii (Bréthes, 1923), Ev. evandroi (Costa, Lima & Antunes, 1936), Ev. lenti (Mangabeira, 1938), and Ev. termitophila (Martins, Falcão & Silva, 1964), besides Lu. longipalpis. Our study indicates favorable conditions for VL spreading in Itaúna due to the presence of Lu. longipalpis and Le. infantum-infected phlebotomine sand flies.

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