scholarly journals Transmission of the human relapsing fever spirochete Borrelia persica by the argasid tick Ornithodoros tholozani involves blood meals from wildlife animal reservoirs and mainly transstadial transfer

2021 ◽  
Author(s):  
Gabriela Kleinerman ◽  
Tom Eshed ◽  
Yaarit Nachum-Biala ◽  
Roni King ◽  
Gad Baneth
Keyword(s):  
Blood Meal ◽  
Human Infection ◽  
Relapsing Fever ◽  
Red Foxes ◽  
Wild Mammals ◽  
Tick Infection ◽  
Wild Canids ◽  
Tick Transmission ◽  
Argasid Tick ◽  
Blood Meals

Borrelia persica transmitted by the argasid tick Ornithodoros tholozani causes human tick-borne relapsing fever in the Middle East and Central Asia. Infection is acquired often when visiting tick-infested caves and reported to be transmitted mainly transovarially between ticks occasionally infecting humans. To study the epidemiology of this infection, ticks were trapped in 24 caves in 12 geographic zones covering all of Israel and identified morphologically. DNA was extracted from larvae, nymphs and adult stages from each location and PCR followed by DNA sequencing was performed to identify Borrelia infection, tick species, and tick blood-meal sources. 51,472 argasid ticks were collected from 16 of 24 caves surveyed. 2,774 O. tholozani were analyzed and 72 (2.6%) from nine caves were PCR-positive for B. persica. Infection rates in male, female and nymphal ticks (4.4%, 3% and 3.2%, respectively) were higher than in larva (p<0.001) with only 3 (0.04%) positive larvae. Presence of blood-meal was associated with B. persica infection in ticks (p=0.003), and blood-meals of golden jackals, red foxes and Cairo spiny mouse were associated with infection (p≤0.043). PCR survey of 402 wild mammals revealed B. persica infection with the highest rate in social voles (22%), red foxes (16%), golden jackals (8%) and Cairo spiny mice (3%). In conclusion, although transovarial tick transmission of B. persica occurs at low levels, ticks apparently acquire infection mainly from wildlife canid and rodents and may eventually transmit relapsing fever borreliosis to humans who enter their habitat. Importance Borrelia persica is a spirochete that causes tick-borne relapsing fever in humans in an area that spans from India to the Mediterranean. Until now it was thought that the soft tick vector of this infection, Orhinthodoros tholozani, is also its main reservoir and it transmits B. persica mostly transovarially between tick generations. This study showed that tick infection with B. persica is associated with feeding blood from wild jackals, foxes and rodents, and that transovarial transmission is minimal. Since O. tholozani ticks are found in isolated caves and ruins, it is assumed that wild canids who migrate over long distances have a major role in the transmission of B. persica between remote tick populations, and its then maintained locally also by rodents and eventually transferred to humans during tick bites. Prevention of human infection could be achieved by restricting entrance of canines and humans to habitats with O. tholozani populations.

scholarly journals Understanding mosquito host-choice behaviour: a new and low-cost method of identifying the sex of human hosts from mosquito blood meals

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fiona Teltscher ◽  
Sophie Bouvaine ◽  
Gabriella Gibson ◽  
Paul Dyer ◽  
Jennifer Guest ◽  
...  
Keyword(s):  
Blood Meal ◽  
Host Species ◽  
Disease Transmission ◽  
Low Cost ◽  
Host Choice ◽  
Epidemiological Models ◽  
Choice Behaviour ◽  
Vector Borne ◽  
Transmission Models ◽  
Blood Meals

Abstract Background Mosquito-borne diseases are a global health problem, causing hundreds of thousands of deaths per year. Pathogens are transmitted by mosquitoes feeding on the blood of an infected host and then feeding on a new host. Monitoring mosquito host-choice behaviour can help in many aspects of vector-borne disease control. Currently, it is possible to determine the host species and an individual human host from the blood meal of a mosquito by using genotyping to match the blood profile of local inhabitants. Epidemiological models generally assume that mosquito biting behaviour is random; however, numerous studies have shown that certain characteristics, e.g. genetic makeup and skin microbiota, make some individuals more attractive to mosquitoes than others. Analysing blood meals and illuminating host-choice behaviour will help re-evaluate and optimise disease transmission models. Methods We describe a new blood meal assay that identifies the sex of the person that a mosquito has bitten. The amelogenin locus (AMEL), a sex marker located on both X and Y chromosomes, was amplified by polymerase chain reaction in DNA extracted from blood-fed Aedes aegypti and Anopheles coluzzii. Results AMEL could be successfully amplified up to 24 h after a blood meal in 100% of An. coluzzii and 96.6% of Ae. aegypti, revealing the sex of humans that were fed on by individual mosquitoes. Conclusions The method described here, developed using mosquitoes fed on volunteers, can be applied to field-caught mosquitoes to determine the host species and the biological sex of human hosts on which they have blood fed. Two important vector species were tested successfully in our laboratory experiments, demonstrating the potential of this technique to improve epidemiological models of vector-borne diseases. This viable and low-cost approach has the capacity to improve our understanding of vector-borne disease transmission, specifically gender differences in exposure and attractiveness to mosquitoes. The data gathered from field studies using our method can be used to shape new transmission models and aid in the implementation of more effective and targeted vector control strategies by enabling a better understanding of the drivers of vector-host interactions.

scholarly journals Triatomine Feeding Profiles and Trypanosoma cruzi Infection, Implications in Domestic and Sylvatic Transmission Cycles in Ecuador

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 42
Author(s):  
Sofía Ocaña-Mayorga ◽  
Juan José Bustillos ◽  
Anita G. Villacís ◽  
C. Miguel Pinto ◽  
Simone Frédérique Brenière ◽  
...  
Keyword(s):  
Blood Meal ◽  
Mitochondrial Gene ◽  
Intestinal Content ◽  
Human Infection ◽  
Dispersal Capacity ◽  
Transmission Cycle ◽  
Rhodnius Ecuadoriensis ◽  
Transmission Cycles ◽  
Endemic Areas ◽  
Southern Highland

Understanding the blood meal patterns of insects that are vectors of diseases is fundamental in unveiling transmission dynamics and developing strategies to impede or decrease human–vector contact. Chagas disease has a complex transmission cycle that implies interactions between vectors, parasites and vertebrate hosts. In Ecuador, limited data on human infection are available; however, the presence of active transmission in endemic areas has been demonstrated. The aim of this study was to determine the diversity of hosts that serve as sources of blood for triatomines in domestic, peridomestic and sylvatic transmission cycles, in two endemic areas of Ecuador (central coastal and southern highland regions). Using conserved primers and DNA extracted from 507 intestinal content samples from five species of triatomines (60 Panstrongylus chinai, 17 Panstrongylus howardi, 1 Panstrongylus rufotuberculatus, 427 Rhodnius ecuadoriensis and 2 Triatoma carrioni) collected from 2006 to 2013, we amplified fragments of the cytb mitochondrial gene. After sequencing, blood meal sources were identified in 416 individuals (146 from central coastal and 270 from southern highland regions), achieving ≥ 95% identity with GenBank sequences (NCBI-BLAST tool). The results showed that humans are the main source of food for triatomines, indicating that human–vector contact is more frequent than previously thought. Although other groups of mammals, such as rodents, are also an available source of blood, birds (particularly chickens) might have a predominant role in the maintenance of triatomines in these areas. However, the diversity of sources of blood found might indicate a preference driven by triatomine species. Moreover, the presence of more than one source of blood in triatomines collected in the same place indicated that dispersal of vectors occurs regardless the availability of food. Dispersal capacity of triatomines needs to be evaluated to propose an effective strategy that limits human–vector contact and, in consequence, to decrease the risk of T. cruzi transmission.

Longevity of Anopheles maculipennis race atroparvus, van Thiel, at controlled Temperature and Humidity after one Blood Meal

1939 ◽  
Vol 30 (3) ◽  
pp. 295-301 ◽  
Author(s):  
H. S. Leeson
Keyword(s):  
Blood Meal ◽  
Small Proportion ◽  
Feeding Period ◽  
Anopheles Maculipennis ◽  
Culex Fatigans ◽  
Temperature And Humidity ◽  
Males And Females ◽  
Blood Meals

From January to July 1938, experiments with Anopheles maculipennis race atroparvus, Van Thiel, were undertaken to discover whether humidity and the age at which the females fed influenced their longevity. It was found that they lived longer at higher than at lower humidities; that most of the females which fed did so in the first three days; that those which fed on the second day after emergence lived longer than those which fed at other ages; and that the feeding period was slightly extended in the later experiments, though only a small proportion lived long enough to take their first blood meals on the fourth and fifth days.Rather more than 50 per cent. of each batch of newly emerged adults were females.A large proportion of the deaths of unfed males and females occurred during the first three days, most of them on the second day; this mortality decreased in successive experiments.Culex fatigans, Wied., behaved similarly.

scholarly journals The Relapsing Fever Spirochete Borrelia hermsiiContains Multiple, Antigen-Encoding Circular Plasmids That Are Homologous to the cp32 Plasmids of Lyme Disease Spirochetes

2000 ◽  
Vol 68 (7) ◽  
pp. 3900-3908 ◽  
Author(s):  
Brian Stevenson ◽  
Stephen F. Porcella ◽  
Katrina L. Oie ◽  
Cecily A. Fitzpatrick ◽  
Sandra J. Raffel ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Direct Detection ◽  
Human Infection ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
Functional Studies ◽  
Dna Library ◽  
Multiple Antigen ◽  
Antigenic Proteins

ABSTRACT Borrelia hermsii, an agent of tick-borne relapsing fever, was found to contain multiple circular plasmids approximately 30 kb in size. Sequencing of a DNA library constructed from circular plasmid fragments enabled assembly of a composite DNA sequence that is homologous to the cp32 plasmid family of the Lyme disease spirochete,B. burgdorferi. Analysis of another relapsing fever bacterium, B. parkeri, indicated that it contains linear homologs of the B. hermsii and B. burgdorfericp32 plasmids. The B. hermsii cp32 plasmids encode homologs of the B. burgdorferi Mlp and Bdr antigenic proteins and BlyA/BlyB putative hemolysins, but homologs of B. burgdorferi erp genes were absent. Immunoblot analyses demonstrated that relapsing fever patients produced antibodies to Mlp proteins, indicating that those proteins are synthesized by the spirochetes during human infection. Conservation of cp32-encoded genes in differentBorrelia species suggests that their protein products serve functions essential to both relapsing fever and Lyme disease spirochetes. Relapsing fever borreliae replicate to high levels in the blood of infected animals, permitting direct detection and possible functional studies of Mlp, Bdr, BlyA/BlyB, and other cp32-encoded proteins in vivo.

scholarly journals Population Structure of Harvested Red Foxes (Vulpes vulpes) and Coyotes (Canis latrans) on Prince Edward Island, Canada

2013 ◽  
Vol 126 (4) ◽  
pp. 288 ◽  
Author(s):  
Wendela Wapenaar ◽  
Fiep De Bie ◽  
David Johnston ◽  
Ryan M. O'Handley ◽  
Herman W. Barkema
Keyword(s):  
Population Dynamics ◽  
Wildlife Management ◽  
Urban Areas ◽  
Vulpes Vulpes ◽  
Prince Edward Island ◽  
Canis Latrans ◽  
Habitat Type ◽  
Red Foxes ◽  
Wild Canids ◽  
Agricultural Areas

An understanding of the population dynamics and habitat of wild Red Foxes (Vulpes vulpes) and Coyotes (Canis latrans) is a prerequisite to wildlife management. This information is also important in assessing the risk these wild canids pose to the public and domestic animals. On Prince Edward Island, information on age, sex, reproductive activity, and habitat use of 271 Red Foxes and 201 Coyotes was collected in the hunting and trapping season of 2004–2005. The estimated age of Red Foxes and Coyotes ranged from 0.5 to 13.5 years. A large proportion of harvested Red Foxes and Coyotes (58% and 48%, respectively) consisted of juveniles. The sex ratio was not significantly different from 1:1 for either species. Average litter size was 5.0 and 5.2 for Red Foxes and Coyotes, respectively. Number of placental scars ranged from 0 to 7 in Red Foxes and from 0 to 11 in Coyotes. Agricultural areas were the main habitat type (52%) of harvested Red Foxes. For harvested Coyotes, forest was the main habitat (44%), followed closely by agricultural areas (43%). Urban areas were a significant part (13%) of the habitat of Red Foxes. These data can be used to monitor population dynamics over time, provide information for wildlife management, and provide information on potential risk areas for disease transmission by wild canids.

A simple method for marking haematophagous insects during the act of feeding

1963 ◽  
Vol 54 (3) ◽  
pp. 379-382 ◽  
Author(s):  
R. H. Knight ◽  
H. A. W. Southon
Keyword(s):  
Aqueous Solution ◽  
Blood Meal ◽  
Trypan Blue ◽  
The Other ◽  
Fresh Blood ◽  
Glossina Morsitans ◽  
Simple Method ◽  
Narrow Strip ◽  
Chromatographic Procedure ◽  
Blood Meals

Blood-meals of two species of haematophagous insects, Glossina morsitans Westw. and Aedes (Stegomyia) aegypti (L.), have been ‘ marked ’ by allowing groups of adults to feed on an ox to which an aqueous solution containing 4 g. of trypan blue had previously been administered intravenously. The dyestuff is detected by a paper chromatographic procedure in which the blood-meal, mixed with 0·1N NaOH, is applied to a narrow strip of Whatman No. 1 chromatographic filter paper and the chromatogram is developed in 0·1N NaOH. Under these conditions, trypan blue remains at the origin, whereas the other coloured components of the blood-meal move away from the point of application. The duration of the mark in the ox and in the insects has been examined. The trypan blue was detected in four out of six fresh blood-meals of Glossina taken 38 days after injection of the dye into the ox, in six out of six examples of Glossina examined two days after blood-meals taken 24 days after the injection, in four out of six examples of Glossina examined eight days after blood-meals taken immediately following the injection, in six out of six examples of Aedes one day after blood-meals taken 14 days after the injection and in six out of six examples of Aedes two days after blood-meals taken immediately following the injection.

Nutritional condition and survival of red foxes with sarcoptic mange

2002 ◽  
Vol 80 (1) ◽  
pp. 154-161 ◽  
Author(s):  
Tabetha J Newman ◽  
Philip J Baker ◽  
Stephen Harris
Keyword(s):  
Survival Time ◽  
Body Mass ◽  
Early Stage ◽  
Class Ii ◽  
Sarcoptic Mange ◽  
Class I ◽  
Survival Times ◽  
Red Foxes ◽  
Fat Reserves ◽  
Wild Canids

We aimed to compare body condition, urine profiles, and survival times between red foxes (Vulpes vulpes) that were infected with sarcoptic mange and others that were uninfected. First we compared the relative body mass, chest girth, fat reserves, and urinary urea nitrogen:creatinine (UN:C) ratios of red foxes in three infection classes: uninfected, class I (no hyperkeratotic mange), and class II (hyperkeratotic mange present). Infected foxes had lower relative body mass and lower fat reserves than uninfected foxes. Both fat reserves and urinary UN:C data suggested that class II infection was more severe than class I infection. Urinary UN:C in class II foxes was significantly higher than in uninfected and class I foxes, indicating accelerated muscle catabolism in class II foxes. Elevated urinary UN:C has never been recorded in wild canids, indicating that these animals had been subjected to a period of prolonged starvation or chronic undernourishment. We also estimated the survival time of foxes once infected with mange from capture–mark–recapture data. Twenty-five foxes were caught at an early stage of infection and had a known date of death. Although some were treated once with ivermectin they did not recover, and their survival time was no longer than that of untreated infected foxes. Untreated infected adults survived for up to 271 days after capture, which is longer than previously suggested. Overall, the survival time of infected foxes was roughly one-fifth of that of uninfected foxes (matched by age and sex).

scholarly journals Assessing the blood-host plasticity and dispersal rate of the malaria vector Anopheles coluzzii

2018 ◽  
Author(s):  
James Orsborne ◽  
Luis Furuya-Kanamori ◽  
Claire L. Jeffries ◽  
Mojca Kristan ◽  
Abdul Rahim Mohammed ◽  
...  
Keyword(s):  
Blood Meal ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Host Choice ◽  
Anopheles Coluzzii ◽  
Dispersal Rate ◽  
Blood Digestion ◽  
Novel Method ◽  
Blood Meal Digestion ◽  
Blood Meals

AbstractDifficulties with observing the dispersal of insect vectors in the field have hampered understanding of several aspects of their behaviour linked to disease transmission. Here, a novel method based on detection of blood-meal sources is introduced to inform two critical and understudied mosquito behaviours: plasticity in the malaria vector’s blood-host choice and vector dispersal. Strategically located collections of Anopheles coluzzii from a malaria-endemic village of southern Ghana showed statistically significant variation in host species composition of mosquito blood-meals. Trialling a new sampling approach gave the first estimates for the remarkably local spatial scale across which host choice is plastic. Using quantitative PCR, the blood-meal digestion was then quantified for field-caught mosquitoes and calibrated according to timed blood digestion in colony mosquitoes. We demonstrate how this new ‘molecular Sella score’ approach can be used to estimate the dispersal rate of blood-feeding vectors caught in the field.

scholarly journals Blood meal analysis: host-feeding patterns of biting midges (Diptera, Ceratopogonidae, Culicoides Latreille) in Slovakia

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 58
Author(s):  
Zuzana Kasičová ◽  
Andrea Schreiberová ◽  
Andrea Kimáková ◽  
Alica Kočišová
Keyword(s):  
Blood Meal ◽  
Lepus Europaeus ◽  
Host Feeding ◽  
Apodemus Flavicollis ◽  
Small Rodents ◽  
Biting Midges ◽  
Culicoides Obsoletus ◽  
Blood Meal Analysis ◽  
Trophic Preferences ◽  
Blood Meals

Biting midges of the genus Culicoides are vectors of important pathogens affecting domestic and wild animals and have played a major role in the re-emergence of new outbreaks of bluetongue (BTV) and Schmallenberg (SBV) viruses in Europe. To determine vector-host specificity, trophic preference from blood meal analysis is of major importance in the surveillance of arthropod-borne diseases. Of 28,752 specimens collected, we identified 17 Culicoides species and investigated a total of 48 host sequences from the blood meals. Culicoides obsoletus/C. scoticus, C. dewulfi, C. pulicaris, C. lupicaris, C. punctatus, C. newsteadi, C. riethi, and C. furcillatus were found to feed on mammals (cattle, horses, and humans), birds (domestic chickens), small rodents (Apodemus flavicollis), and hares (Lepus europaeus). To our knowledge, this is the first study investigating trophic preferences of Culicoides spp. in Slovakia. This study demonstrated that Culicoides species are able to feed on domesticated host vertebrates as well as birds, rodents, and humans.

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