Culicoides (Avaritia) gornostaevae Mirzaeva, 1984 (Diptera: Ceratopogonidae) - a possible vector species of the Obsoletus group new to the European fauna

Abstract Background Vector control through long-lasting insecticidal nets (LLINs) and focal indoor residual spraying (IRS) is a major component of the Tanzania national malaria control strategy. In mainland Tanzania, IRS has been conducted annually around Lake Victoria basin since 2007. Due to pyrethroid resistance in malaria vectors, use of pyrethroids for IRS was phased out and from 2014 to 2017 pirimiphos-methyl (Actellic® 300CS) was sprayed in regions of Kagera, Geita, Mwanza, and Mara. Entomological surveillance was conducted in 10 sprayed and 4 unsprayed sites to determine the impact of IRS on entomological indices related to malaria transmission risk. Methods WHO cone bioassays were conducted monthly on interior house walls to determine residual efficacy of pirimiphos-methyl CS. Indoor CDC light traps with or without bottle rotator were hung next to protected sleepers indoors and also set outdoors (unbaited) as a proxy measure for indoor and outdoor biting rate and time of biting. Prokopack aspirators were used indoors to capture resting malaria vectors. A sub-sample of Anopheles was tested by PCR to determine species identity and ELISA for sporozoite rate. Results Annual IRS with Actellic® 300CS from 2015 to 2017 was effective on sprayed walls for a mean of 7 months in cone bioassay. PCR of 2016 and 2017 samples showed vector populations were predominantly Anopheles arabiensis (58.1%, n = 4,403 IRS sites, 58%, n = 2,441 unsprayed sites). There was a greater proportion of Anopheles funestus sensu stricto in unsprayed sites (20.4%, n = 858) than in sprayed sites (7.9%, n = 595) and fewer Anopheles parensis (2%, n = 85 unsprayed, 7.8%, n = 591 sprayed). Biting peaks of Anopheles gambiae sensu lato (s.l.) followed periods of rainfall occurring between October and April, but were generally lower in sprayed sites than unsprayed. In most sprayed sites, An. gambiae s.l. indoor densities increased between January and February, i.e., 10–12 months after IRS. The predominant species An. arabiensis had a sporozoite rate in 2017 of 2.0% (95% CI 1.4–2.9) in unsprayed sites compared to 0.8% (95% CI 0.5–1.3) in sprayed sites (p = 0.003). Sporozoite rates were also lower for An. funestus collected in sprayed sites. Conclusion This study contributes to the understanding of malaria vector species composition, behaviour and transmission risk following IRS around Lake Victoria and can be used to guide malaria vector control strategies in Tanzania.

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Progress towards elimination of lymphatic filariasis in the Americas region

International Health ◽

10.1093/inthealth/ihaa048 ◽

2020 ◽

Vol 13 (Supplement_1) ◽

pp. S33-S38

Author(s):

Gilberto Fontes ◽

Eliana Maria Mauricio da Rocha ◽

Ronaldo Guilherme Carvalho Scholte ◽

Rubén Santiago Nicholls

Keyword(s):

Dominican Republic ◽

Lymphatic Filariasis ◽

Wuchereria Bancrofti ◽

World Health ◽

Vector Species ◽

Effective Coverage ◽

The Third ◽

Assessment Survey ◽

Health Organization ◽

Important Progress

Abstract In South and Central America, lymphatic filariasis (LF) is caused by Wuchereria bancrofti, which is transmitted by Culex quinquefasciatus, the only vector species in this region. Of the seven countries considered endemic for LF in the Americas in the last decade, Costa Rica, Suriname and Trinidad and Tobago were removed from the World Health Organization list in 2011. The remaining countries, Brazil, Dominican Republic, Guyana and Haiti, have achieved important progress in recent years. Brazil was the first country in the Americas to stop mass drug administration (MDA) and to establish post-MDA surveillance. Dominican Republic stopped MDA in all LF-endemic foci: La Ciénaga and Southwest passed the third Transmission Assessment Survey (TAS) and the Eastern focus passed TAS-1 in 2018. Haiti passed the TAS and interrupted transmission in >80% of endemic communes, achieving effective drug coverage. Guyana implemented effective coverage in MDAs in 2017 and 2018 and in 2019 scaled up the treatment for 100% of the geographical region, introducing ivermectin in the MDA in order to achieve LF elimination by the year 2026. The Americas region is on its way to eliminating LF transmission. However, efforts should be made to improve morbidity management to prevent disability of the already affected populations.

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The evolution of hard tick-borne relapsing fever borreliae is correlated with vector species rather than geographical distance

BMC Ecology and Evolution ◽

10.1186/s12862-021-01838-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Ranna Nakao ◽

Kentaro Kasama ◽

Bazartseren Boldbaatar ◽

Yoshitoshi Ogura ◽

Hiroki Kawabata ◽

...

Keyword(s):

Core Gene ◽

Genetic Distances ◽

Hard Tick ◽

Vector Species ◽

Relapsing Fever ◽

Strain Isolation ◽

Ecological Features ◽

Geographical Distances ◽

History Of ◽

Hokkaido Island

Abstract Background Relapsing fever (RF) borreliae are arthropod-borne spirochetes and some of them cause human diseases, which are characterized by relapsing or recurring episodes of fever. Recently, it has been classified into two groups: soft tick-borne RF (STRF) borreliae and hard tick-borne RF (HTRF) borreliae. STRF borreliae include classical RF agents and HTRF borreliae, the latter of which include B. miyamotoi, a human pathogen recently identified in Eurasia and North America. Results In this study, we determined the genome sequences of 16 HTRF borreliae strains: 15 B. miyamotoi strains (9 from Hokkaido Island, Japan, 3 from Honshu Island, Japan, and 3 from Mongolia) and a Borrelia sp. tHM16w. Chromosomal gene synteny was highly conserved among the HTRF strains sequenced in this study, even though they were isolated from different geographic regions and different tick species. Phylogenetic analysis based on core gene sequences revealed that HTRF and STRF borreliae are clearly distinguishable, with each forming a monophyletic group in the RF borreliae lineage. Moreover, the evolutionary relationships of RF borreliae are consistent with the biological and ecological features of each RF borreliae sublineage and can explain the unique characteristics of Borrelia anserina. In addition, the pairwise genetic distances between HTRF borreliae strains were well correlated with those of vector species rather than with the geographical distances between strain isolation sites. This result suggests that the genetic diversification of HTRF borreliae is attributed to the speciation of vector ticks and that this relationship might be required for efficient transmission of HTRF borreliae within vector ticks. Conclusions The results of the present study, together with those from previous investigations, support the hypothesis that the common ancestor of borreliae was transmitted by hard-bodied ticks and that only STRF borreliae switched to using soft-bodied ticks as a vector, which was followed by the emergence of Borrelia recurrentis, lice-borne RF borreliae. Our study clarifies the phylogenetic relationships between RF borreliae, and the data obtained will contribute to a better understanding of the evolutionary history of RF borreliae.

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Thermal limits of wild and laboratory strains of two African malaria vector species, Anopheles arabiensis and Anopheles funestus

Malaria Journal ◽

10.1186/1475-2875-11-226 ◽

2012 ◽

Vol 11 (1) ◽

Cited By ~ 34

Author(s):

Candice L Lyons ◽

Maureen Coetzee ◽

John S Terblanche ◽

Steven L Chown

Keyword(s):

Malaria Vector ◽

Anopheles Arabiensis ◽

Anopheles Funestus ◽

Vector Species ◽

Thermal Limits

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Mealybug Transmission of Grapevine Leafroll Viruses: An Analysis of Virus–Vector Specificity

Phytopathology ◽

10.1094/phyto-100-8-0830 ◽

2010 ◽

Vol 100 (8) ◽

pp. 830-834 ◽

Cited By ~ 77

Author(s):

Chi-Wei Tsai ◽

Adib Rowhani ◽

Deborah A. Golino ◽

Kent M. Daane ◽

Rodrigo P. P. Almeida

Keyword(s):

Plant Pathogens ◽

Phylogenetic Analyses ◽

Virus Vector ◽

Disease Spread ◽

Virus Species ◽

Vector Species ◽

Vector Transmission ◽

Planococcus Ficus ◽

Grapevine Leafroll Disease ◽

Leafroll Disease

To understand ecological factors mediating the spread of insect-borne plant pathogens, vector species for these pathogens need to be identified. Grapevine leafroll disease is caused by a complex of phylogenetically related closteroviruses, some of which are transmitted by insect vectors; however, the specificities of these complex virus–vector interactions are poorly understood thus far. Through biological assays and phylogenetic analyses, we studied the role of vector-pathogen specificity in the transmission of several grapevine leafroll-associated viruses (GLRaVs) by their mealybug vectors. Using plants with multiple virus infections, several virus species were screened for vector transmission by the mealybug species Planococcus ficus and Pseudococcus longispinus. We report that two GLRaVs (-4 and -9), for which no vector transmission evidence was available, are mealybug-borne. The analyses performed indicated no evidence of mealybug–GLRaV specificity; for example, different vector species transmitted GLRaV-3 and one vector species, Planococcus ficus, transmitted five GLRaVs. Based on available data, there is no compelling evidence of vector–virus specificity in the mealybug transmission of GLRaVs. However, more studies aimed at increasing the number of mealybug species tested as vectors of different GLRaVs are necessary. This is especially important given the increasing importance of grapevine leafroll disease spread by mealybugs in vineyards worldwide.

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Epidemiology of Lyme Disease

Canadian Journal of Infectious Diseases ◽

10.1155/1991/852310 ◽

1991 ◽

Vol 2 (2) ◽

pp. 58-60

Author(s):

Dennis J White

Keyword(s):

Public Health ◽

Lyme Disease ◽

Disease Surveillance ◽

Vector Species ◽

Potential Vector ◽

Public Health Agencies ◽

Laboratory Services ◽

Health Agencies ◽

Surveillance Programs ◽

Risk Of Exposure

Investigation of the epidemiology of Lyme disease depends upon information generated from several sources. Human disease surveillance can be conducted by both passive and active means involving physicians, public health agencies and laboratories. Passive and active tick surveillance programs can document the extent of tick-borne activity, identify the geographic range of potential vector species, and determine the relative risk of exposure to Lyme disease in specific areas. Standardized laboratory services can play an important role in providing data. Epidemiologists can gain a better understanding of Lyme disease through the collection of data from such programs. The interpretation of data and provision of information to the medical and general communities are important functions of public health agencies.

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Biosyslematics and distribution of Simuliid vectors of human onchocerciasis in South America

Memórias do Instituto Oswaldo Cruz ◽

10.1590/s0074-02761988000400001 ◽

1988 ◽

Vol 83 (4) ◽

pp. 399-403 ◽

Cited By ~ 1

Author(s):

A. J. Shelley

Keyword(s):

Latin America ◽

South America ◽

Taxonomic Status ◽

Vector Species ◽

Distribution Maps ◽

Medical Importance

A brief review is given of the taxonomic status, biology and medical importance, and distribution of the vectors of human onchocerciasis in Latin America. Key reference works are cited and distribution maps of each vector species in relation to the known onchocerciasis foci are given.

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Equine piroplasmosis status in the UK: an assessment of laboratory diagnostic submissions and techniques

Veterinary Record ◽

10.1136/vr.104855 ◽

2018 ◽

Vol 184 (3) ◽

pp. 95-95 ◽

Cited By ~ 9

Author(s):

Robert M Coultous ◽

Paul Phipps ◽

Charlie Dalley ◽

Jane Lewis ◽

Toni-Ann Hammond ◽

...

Keyword(s):

Animal Health ◽

Health Agency ◽

Clinical Samples ◽

Vector Species ◽

Equine Piroplasmosis ◽

Tick Vector ◽

Increased Risk ◽

The Uk ◽

Tick Vectors ◽

Health Trust

Equine piroplasmosis (EP) has historically been of minor concern to UK equine practitioners, primarily due to a lack of competent tick vectors. However, increased detection of EP tick vector species in the UK has been reported recently. EP screening is not currently required for equine importation, and when combined with recent relaxations in movement regulations, there is an increased risk regarding disease incursion and establishment into the UK. This study evaluated the prevalence of EP by both serology and PCR among 1242 UK equine samples submitted for EP screening between February and December 2016 to the Animal and Plant Health Agency and the Animal Health Trust. Where information was available, 81.5 per cent of submissions were for the purpose of UK export testing, and less than 0.1 per cent for UK importation. Serological prevalence of EP was 8.0 per cent, and parasite DNA was found in 0.8 per cent of samples. A subsequent analysis of PCR sensitivity in archived clinical samples indicated that the proportion of PCR-positive animals is likely to be considerably higher. The authors conclude that the current threat imposed by UK carrier horses is not adequately monitored and further measures are required to improve national biosecurity and prevent endemic disease.

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