Average Infection Prevalence Research Articles

Fauna of ectoparasites of fur-bearing animals in fur farms of the Tver region

Fur farming is a branch of agriculture that specializes in breeding fur-bearing animals in order to obtain valuable fur skins from them. An important task of fur farming is to increase the quantity and quality of products obtained through intensification of production. This may lead to an increase in the number of outbreaks of infectious and invasive diseases. Ectoparasites negatively affect the quality of fur and can lead to the death of young animals. We conducted a study of the ectoparasite fauna in fur farms of the Tver region: «Savvatyevo» and «Mekha». We examined three types of furbearing animals: fox, American mink, and ferret. We performed a clinical examination of the animals; we examined the fur to detect fleas; we examined parasitological material from the auricle and external auditory canal under a microscope, we caught and determined the type of zoophilic flies. Ear mites O. cynotis have been reported in foxes and polecats. In foxes, infection rates: age 5 months – prevalence of infection 80,95%, intensity of infection 20,00 copies, at the age of 1 year – 86,67% and 6,67 copies, at the age of 2 years – 100,00% and 8,10 copies. For ferrets: age 3 months - no ear mites detected, age 1-year prevalence of infection 86,67%, intensity of infection 2,50 copies, age 2 years – 100,00% and 14,20 copies. Taking these data into account, all age groups of foxes support the invasive potential of O. cynotis equally, being a source of infection of new animals and a reservoir of the pathogen. Fleas C. (M.) s. sciurorum have been recorded in minks. The average prevalence of infection in adult males and females is 63,3%, the average intensity of infection is 11.6 specimens. The prevalence of infection of zoophilic flies was: M. domestica – 45,1%, L. caesar – 28,6%, P. regina – 11,9%, C. uralensis – 9,6%, F. canicularis – 4,8%. The number of flies in the shad was up to 30 individuals/m2. The data obtained indicate the wide distribution of arachnoenthomosis among fur-bearing animals in fur farms of the Tver region, which makes it urgent to introduce new schemes for the control and prevention of ectoparasites.

What Is the Economic Benefit of Annual COVID-19 Vaccination From the Adult Individual Perspective?

With coronavirus disease 2019 (COVID-19) vaccination no longer mandated by many businesses/organizations, it is now up to individuals to decide whether to get any new boosters/updated vaccines going forward. We developed a Markov model representing the potential clinical/economic outcomes from an individual perspective in the United States of getting versus not getting an annual COVID-19 vaccine. For an 18-49 year old, getting vaccinated at its current price ($60) can save the individual on average $30-$603 if the individual is uninsured and $4-$437 if the individual has private insurance, as long as the starting vaccine efficacy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is ≥50% and the weekly risk of getting infected is ≥0.2%, corresponding to an individual interacting with 9 other people in a day under Winter 2023-2024 Omicron SARS-CoV-2 variant conditions with an average infection prevalence of 10%. For a 50-64 year old, these cost-savings increase to $111-$1278 and $119-$1706 for someone without and with insurance, respectively. The risk threshold increases to ≥0.4% (interacting with 19 people/day), when the individual has 13.4% preexisting protection against infection (eg, vaccinated 9 months earlier). There is both clinical and economic incentive for the individual to continue to get vaccinated against COVID-19 each year.

Prevalence of SARS-CoV-2 Infection among Children and Adults in 15 US Communities, 2021

During January-August 2021, the Community Prevalence of SARS-CoV-2 Study used time/location sampling to recruit a cross-sectional, population-based cohort to estimate SARS-CoV-2 seroprevalence and nasal swab sample PCR positivity across 15 US communities. Survey-weighted estimates of SARS-CoV-2 infection and vaccine willingness among participants at each site were compared within demographic groups by using linear regression models with inverse variance weighting. Among 22,284 persons >2 months of age and older, median prevalence of infection (prior, active, or both) was 12.9% across sites and similar across age groups. Within each site, average prevalence of infection was 3 percentage points higher for Black than White persons and average vaccine willingness was 10 percentage points lower for Black than White persons and 7 percentage points lower for Black persons than for persons in other racial groups. The higher prevalence of SARS-CoV-2 infection among groups with lower vaccine willingness highlights the disparate effect of COVID-19 and its complications.

Ceratonova shasta infection in lower Feather River Chinook juveniles and trends in water-borne spore stages

We performed a five-year (2015–2020) survey of juvenile natural Chinook Salmon (Oncorhynchus tshawytscha), adult salmon carcasses, and river water from the lower Feather River to determine infection prevalence, distribution, and spore quantity of the myxozoan parasite Ceratonova shasta. Average prevalence of infection in juvenile salmon collected from the high flow channel ranged from 45–58% depending on assay method. Initial infection of fry and detection of actinospore stage in river water began in late January or early February. Overt disease occurred in March and was lethal. Infection of the gill was detected weeks ahead of intestinal infection. Water-borne spore measurement and fish infection demonstrate an infectious zone beginning at the outlet of the Thermalito Afterbay. This zone is expanding downriver past the confluence of the Yuba River. Adult carcasses produce billions of myxospores annually that move downriver over the winter. C. shasta infection is one of several factors (predation, limited rearing habitat, elevated water temperature, water withdrawal, etc.) limiting natural Chinook Salmon recruitment in the Feather River.

Long‐term trends and seasonal variation in host density, temperature, and nutrients differentially affect chytrid fungi parasitising lake phytoplankton

Abstract Parasites are generally considered the most commonly occurring type of consumers, yet their biomass and population dynamics are rarely quantified at community level. Here, we used 12 years of weekly or fortnightly monitoring data (518 time points) to determine the occurrence of chytrids, fungal parasites of phytoplankton, to assess their seasonality and long‐term (seasonally‐detrended) dynamics in the pelagic plankton community of a temperate, eutrophic, and polymictic lake. Chytrid infections were observed in c. 75% of all samples with recurrent infections in multiple host taxa. Infection prevalence was highest in spring, but infections occurred throughout the entire year with an average of 2.3 host taxa infected per time point (ranging from 0 to 10 host taxa) and an average infection prevalence of 2.78% (ranging from 0% to 47.35%). Infected host biomass equalled that of the carnivorous zooplankton and decreased over time, while infection prevalence remained unchanged. Seasonal infection prevalence increased with phytoplankton biomass, but decreased with increasing temperature and phosphorus concentrations, reflecting that peak prevalence occurred in spring when temperature and phosphorus concentrations were relatively low. In contrast, seasonally‐detrended prevalence increased with temperature, but decreased with increasing phosphorus concentrations. Chytrids are a common component of the pelagic plankton community with sizeable biomass and removing an—at times—substantial proportion of the primary production, challenging the long‐standing underrepresentation of parasites in ecological studies. Chytrids responded differentially to seasonal variation and long‐term trends in host density, water temperature and nutrient availability, highlighting the need to disentangle seasonal signals from long‐term changes.

Parasite dynamics in North American monarchs predicted by host density and seasonal migratory culling.

Insect-pathogen dynamics can show seasonal and inter-annual variations that covary with fluctuations in insect abundance and climate. Long-term analyses are especially needed to track parasite dynamics in migratory insects, in part because their vast habitat ranges and high mobility might dampen local effects of density and climate on infection prevalence. Monarch butterflies Danaus plexippus are commonly infected with the protozoan Ophryocystis elektroscirrha (OE). Because this parasite lowers monarch survival and flight performance, and because migratory monarchs have experienced declines in recent decades, it is important to understand the patterns and drivers of infection. Here we compiled data on OE infection spanning 50years, from wild monarchs sampled in the United States, Canada and Mexico during summer breeding, fall migrating and overwintering periods. We examined eastern versus western North American monarchs separately, to ask how abundance estimates, resource availability, climate and breeding season length impact infection trends. We further assessed the intensity of migratory culling, which occurs when infected individuals are removed from the population during migration. Average infection prevalence was four times higher in western compared to eastern subpopulations. In eastern North America, the proportion of infected monarchs increased threefold since the mid-2000s. In the western region, the proportion of infected monarchs declined sharply from 2000 to 2015, and increased thereafter. For both eastern and western subpopulations, years with greater summer adult abundance predicted greater infection prevalence, indicating that transmission increases with host breeding density. Environmental variables (temperature and NDVI) were not associated with changes in the proportion of infected adults. We found evidence for migratory culling of infected butterflies, based on declines in parasitism during fall migration. We estimated that tens of millions fewer monarchs reach overwintering sites in Mexico as a result of OE, highlighting the need to consider the parasite as a potential threat to the monarch population. Increases in infection among eastern North American monarchs post-2002 suggest that changes to the host's ecology or environment have intensified parasite transmission. Further work is needed to examine the degree to which human practices, such as mass caterpillar rearing and the widespread planting of exotic milkweed, have contributed to this trend.

Inter-annual variation in prevalence of Borrelia burgdorferi sensu stricto and Anaplasma phagocytophilum in host-seeking Ixodes scapularis (Acari: Ixodidae) at long-term surveillance sites in the upper midwestern United States: Implications for public health practice

The geographic range of the blacklegged tick, Ixodes scapularis, and its associated human pathogens have expanded substantially over the past 20 years putting an increasing number of persons at risk for tick-borne diseases, particularly in the upper midwestern and northeastern United States. Prevention and diagnosis of tick-borne diseases rely on an accurate understanding by the public and health care providers of when and where persons may be exposed to infected ticks. While tracking changes in the distribution of ticks and tick-borne pathogens provides fundamental information on risk for tick-borne diseases, metrics that incorporate prevalence of infection in ticks better characterize acarological risk. However, assessments of infection prevalence are more labor intensive and costly than simple measurements of tick or pathogen presence. Our objective was to examine whether data derived from repeated sampling at longitudinal sites substantially influences public health recommendations for Lyme disease and anaplasmosis prevention, or if more constrained sampling is sufficient. Here, we summarize inter-annual variability in prevalence of the agents of Lyme disease (Borrelia burgdorferi s.s.) and anaplasmosis (Anaplasma phagocytophilum) in host-seeking I. scapularis nymphs and adults at 28 longitudinal sampling sites in the Upper Midwestern US (Michigan, Minnesota, and Wisconsin). Infection prevalence was highly variable among sites and among years within sites. We conclude that monitoring infection prevalence in ticks aids in describing coarse acarological risk trends, but setting a fixed prevalence threshold for prevention or diagnostic decisions is not feasible given the observed variability and lack of temporal trends. Reducing repeated sampling of the same sites had minimal impact on regional (Upper Midwest) estimates of average infection prevalence; this information should be useful in allocating scarce public health resources for tick and tick-borne pathogen surveillance, prevention, and control activities.

Abiotic and biotic influences on the performance of two biological control agents, Neochetina bruchi and N. eichhorniae, in the Sacramento-San Joaquin River Delta, California (USA)

Variability in the effectiveness of biological control programs can be due to a myriad of abiotic and biotic interactions. Here, we explore these interactions in relation to the suboptimal biological control on the invasive water hyacinth, Pontederia (=Eichhornia) crassipes, by two weevils, Neochetina bruchi and N. eichhorniae, in the Sacramento-San Joaquin River Delta in California, USA (Delta). We conducted monthly surveys from 2015 to 2017 throughout 1667 km2 to analyze the impacts of temperature, nutrients, river flow, pathogens and genetic variation in relation to the performance of these biological control agents. Weevils (predominantly N. bruchi) demonstrated a positive numerical response to increased nitrogen content in water hyacinth crown and roots. Weevil densities and water hyacinth biomass declined significantly during periods of high river flow. We found negative impacts of cooler temperatures on weevil performance, with a significant lagged-response of weevil densities in the field to water temperature from three months prior and a lack of population growth under laboratory conditions simulating winter air temperatures in the Delta (3.9–13.9 °C). We confirmed the presence of a microsporidian pathogen, with 10.7% average prevalence of infection across four seasons and low infection loads. In addition, we found low genetic diversity of N. bruchi in the Delta compared to native populations, low population genetic structure and a lack of genetic isolation by distance among metapopulations. Overall we conclude that cooler temperatures and periods of high river flow are likely the main factors limiting the current biological control program in the Delta.

English

AbstractCrayfish plague is a severe disease of crayfish that is caused by the oomycete Aphanomyces astaci. Two crayfish hosts of this parasite, Procambarus clarkii and Pacifastacus leniusculus, were imported from North America into Japan and were found to be infected with this parasite. Since the endemic Japanese crayfish, Cambaroides japonicus, has a low resistance to the crayfish plague, infection with this parasite will likely lead to crayfish death. Specimens of both invasive crayfish species were collected across Japan and their infection status was examined using a PCR technique. Aphanomyces astaci was detected in all localities and the average infection prevalence was 67%. Additionally, when the signs of melanization were compared with the results from PCR analyses, it suggested that the DNA detection procedure is more reliable than observation of tissue melanization. Moreover, the relationship between prevalence and water temperature in the field was analyzed, indicated that water temperature influenced the prevalence of A. astaci infection.

The Effect of Habits on Wearing Footwear And hand washing after playing on the ground Against Worms in Primary School Al-Wasliyah In Medan Deli

World Health Organization reported in 2015 more than 1.5 billion population is infected with Ascaris Lumbricoides and in Indonesia on 2013 the average prevalence of infection reaches more than 28%, this study aims to investigate the effect of habits on wearing footwear and hand washing after playing on the ground against worms. The type of this research is Explanatory Research, Data were collected through interviews, documentation and examination of stool, Data was analyzed by univariate, bivariate and multivariate test. The results showed of the effect of wearing footwear Against Worms with p value 0.002 and Exp (B) 43.587 in Confidence Interval 95% is 3.848 until 493.702 and handwashing habits after playing on the ground had an effect on helminthiasis with a p value of 0.007 and Exp (B) of 28.629 in Confidence Interval of 95% between 2.482 to 330.196. According to researchers, worms live on the ground and are very quickly transmitted through the skin of the soles of the feet therefore every child needs to use footwear every time they leave home and the best way to break the chain of transmission of worms by maintaining personal hygiene, such as washing hands with soap after playing on the ground.

Evaluation of the effectiveness of programs combating the invasions of strongyles (Strongylidae) in horses in selected stables of Western Pomerania

The emergence of drug resistance among parasites is a side effect of the common use of chemotherapeutic agents in horses. Combating parasites typically involves routine deworming treatments twice a year (before and after the grazing season). However, in grazing farming this treatment may be insufficient. The aim of the study was to evaluate the effectiveness of programs to combat the invasion of strongyles (Strongylidae) in horses in the selected stables of Western Pomerania. Coprological examination was conducted in 85 horses from three stables located in Western Pomerania. Horses from all three stables remained in the pastures in the period from spring to late autumn, and deworming treatment was performed twice. The examination of horses has found nematodes of the family Strongylidae. The average prevalence of infection in horses in the studs tested was 36.16% for Strongylinae, and 58.49% for Cyathostominae. Administration of the medication twice did not eradicate the invasion of strongyles in the horses investigated. A significant reduction of strongyle invasion was observed directly after treatment, followed by rapid reinvasion. It appears necessary to monitor the effectiveness of deworming treatments by performing parasitological examination of feces. The participating stables should develop and implement new strategies to combat parasitic invasions in horses that will be adapted to the environmental conditions (the life cycle of parasites).

Prevalence of intestinal parasites detected in routine coproscopic methods in dogs and cats from the Masovian voivodeship in 2012-2015

The aim of the study was to analyse canine and feline infections with intestinal parasites basing on routine coproscopic tests. In total 5,809 results were analysed. Infections with Giardia intestinalis (6.93% – in dogs, 4.56% – in cats) and Toxocara spp. (4.07% – in dogs, 5.42% – in cats) were the most commonly noted. The majority of intestinal parasitic infections were identified more frequently in younger animals (under 1 year of age) as compared to older ones. This study showed the increase in the prevalence of coccidia (from 1% to 2.53%) and whipworms (from 2.6% to 3.07%) in dogs and a decrease in roundworm and hookworm related diseases in comparison to previous reports (years 1974-2002). The results showed changes in infection prevalence of both protozoan species (G. intestinalis and Cystoisospora spp.) both in dogs and cats, which suggests that climate conditions had an influence on the infection prevalence of the mentioned species. Moreover, the age of animals had an influence on the infection prevalence of intestinal parasites in dogs. However, there was no influence of both dogs’ and cats’ sex on the average infection prevalence of investigated parasites.

Implications of insecticide resistance for malaria vector control with long-lasting insecticidal nets: a WHO-coordinated, prospective, international, observational cohort study

SummaryBackgroundScale-up of insecticide-based interventions has averted more than 500 million malaria cases since 2000. Increasing insecticide resistance could herald a rebound in disease and mortality. We aimed to investigate whether insecticide resistance was associated with loss of effectiveness of long-lasting insecticidal nets and increased malaria disease burden.MethodsThis WHO-coordinated, prospective, observational cohort study was done at 279 clusters (villages or groups of villages in which phenotypic resistance was measurable) in Benin, Cameroon, India, Kenya, and Sudan. Pyrethroid long-lasting insecticidal nets were the principal form of malaria vector control in all study areas; in Sudan this approach was supplemented by indoor residual spraying. Cohorts of children from randomly selected households in each cluster were recruited and followed up by community health workers to measure incidence of clinical malaria and prevalence of infection. Mosquitoes were assessed for susceptibility to pyrethroids using the standard WHO bioassay test. Country-specific results were combined using meta-analysis.FindingsBetween June 2, 2012, and Nov 4, 2016, 40 000 children were enrolled and assessed for clinical incidence during 1·4 million follow-up visits. 80 000 mosquitoes were assessed for insecticide resistance. Long-lasting insecticidal net users had lower infection prevalence (adjusted odds ratio [OR] 0·63, 95% CI 0·51–0·78) and disease incidence (adjusted rate ratio [RR] 0·62, 0·41–0·94) than did non-users across a range of resistance levels. We found no evidence of an association between insecticide resistance and infection prevalence (adjusted OR 0·86, 0·70–1·06) or incidence (adjusted RR 0·89, 0·72–1·10). Users of nets, although significantly better protected than non-users, were nevertheless subject to high malaria infection risk (ranging from an average incidence in net users of 0·023, [95% CI 0·016–0·033] per person-year in India, to 0·80 [0·65–0·97] per person year in Kenya; and an average infection prevalence in net users of 0·8% [0·5–1·3] in India to an average infection prevalence of 50·8% [43·4–58·2] in Benin).InterpretationIrrespective of resistance, populations in malaria endemic areas should continue to use long-lasting insecticidal nets to reduce their risk of infection. As nets provide only partial protection, the development of additional vector control tools should be prioritised to reduce the unacceptably high malaria burden.FundingBill & Melinda Gates Foundation, UK Medical Research Council, and UK Department for International Development.

Treating village newcomers and travelers for trachoma: Results from ASANTE cluster randomized trial.

Trial designTrachoma is targeted for global elimination. Infection rates with Chlamydia trachomatis are higher in new arrivals to a community and in travelers who leave for extended periods, suggesting they are sources of re-infection. This community-randomized, clinical trial was designed to determine if a surveillance program that targeted newcomers and travelers, identified weekly, would result in more communities achieving levels of infection of ≤1%.Methods52 communities were randomly allocated 1:1 to the control (annual MDA alone if warranted) or intervention arm (annual MDA if warranted, plus a surveillance program to identify and treat newcomers and travelers). In each community, surveys were completed every six months on a random sample of 100 children ages 1–9 years for trachoma and infection. The primary outcome was the proportion of communities in the intervention arm, compared to the control arm, which had a prevalence of infection at ≤1% by 24 months. Registered: clinicaltrials.gov(NCT01767506).ResultsIntervention communities experienced an average of 110 surveillance events per month. At 24 months, 7 (27%) of 26 intervention communities achieved a prevalence of infection ≤1% compared to 4 (15%) of the 26 control communities (odds ratio = 2·6, 95%CI = 0·56–11·9). At 24 months, the average infection prevalence in the intervention communities was 4·8, compared to 6·9 in the control communities (p = ·06).ConclusionDespite surveillance programs for community newcomers and travelers, the proportion of intervention communities with a level of infection ≤1% was lower than expected and not significantly different from control communities.

Great sandeel (Hyperoplus lanceolatus) as a putative transmitter of parasite Contracaecum osculatum (Nematoda: Anisakidae).

In the Baltic Sea, the great sandeel (Hyperoplus lanceolatus), a common fish species that inhabits sandy substrates, is an important element in the diet of marine mammals, sea birds, and piscivorous fish. It can also act as a transmitter of parasites to its predators, but parasitological studies on this species are limited. We sampled great sandeels in April 2016 in two areas of the southern Baltic Sea (SB-south of Bornholm and GG-the Gulf of Gdansk) and found parasitic anisakid nematodes in both locations. The only one species of nematode parasites has been detected: liver worm (Contracaecum osculatum) with average prevalence of infection 8.96%. This is the first study to report on infection of H. lanceolatus with anisakid nematodes in the southern Baltic Sea and our results suggest that the great sandeel may play a role in the transmission of liver worm in the food web of this marine environment.

Variability in prevalence of Cymatocarpus solearis (Trematoda, Brachycoeliidae) in Caribbean spiny lobsters Panulirus argus (Decapoda: Palinuridae) from Bahía de la Ascensión (Mexico)

Cymatocarpus solearis, a brachycoeliid trematode that parasitizes sea turtles, uses spiny lobsters Panulirus argus as second intermediate hosts. We examined variability in infection by C. solearis in Bahía de la Ascensión, Mexico, a tropical bay with a highly productive fishery for P. argus that is based on the extensive use of casitas (large artificial shelters), which can harbor multiple juveniles and adults of this gregarious lobster species. We sampled 3956 lobsters from 466 casitas distributed over three bay zones within two closed seasons and one fishing season. In these lobsters (9.5–115.2mm carapace length, CL), the average infection prevalence was 11.7% but the probability of infection increased significantly with size. Prevalence varied with season but was consistently higher in one zone than in the other two zones. Infection with C. solearis was negatively related with clinical infection with Panulirus argus Virus 1 (PaV1). We also sampled 405 lobsters from the commercial catch obtained throughout the bay at the onset of the fishing season. In these relatively larger lobsters (70.3–168.0mm CL), average prevalence of C. solearis was higher (23.5%) but was not affected by lobster size or sex. Encysted metacercariae occurred in both abdominal and cephalothoracic muscles. The effects of C. solearis on phenotypic traits of P. argus that may potentially impact the host population dynamics and fisheries remain to be investigated.

Natural foci of Borrelia lusitaniae in a mountain region of Central Europe

Lyme borreliosis is the most prevalent tick-borne disease in Europe. It is caused by spirochaetes of the Borrelia burgdorferi sensu lato (s.l.) complex and transmitted to humans by ticks of the genus Ixodes. Borrelia afzelii, Borrelia garinii, and Borrelia valaisiana are the most common genospecies in Central Europe. In contrast, Borrelia lusitaniae predominates in Mediterranean countries such as Portugal, Morocco, and Tunisia. In Slovakia, its prevalence is low and restricted to only a few sites.The aim of our research was to study the expansion of ticks into higher altitudes in the ecosystem of the Malá Fatra mountains (north Slovakia) and their infection with B. burgdorferi s.l. pathogens. Questing ticks were collected by flagging in seven years (2004, 2006–2011) at three different altitudes: low (630–660m above sea level (ASL)), intermediate (720–750m ASL), and high (1040–1070m ASL). Tick abundance was highest at the lowest altitude and lowest at the highest altitude. The average infection prevalence of B. burgdorferi s.l. in nymphs and adults was 16.8% and 36.2%, respectively. The number of infected ticks decreased from 38.5% at the lowest altitude to 4.4% at the highest altitude. B. lusitaniae was the most frequently found genospecies (>60% of the ticks found positive for B. burgdorferi s.l.) in all sites in all the studied years with the exception of 2008 when B. afzelii predominated (62%).Our study confirms the spread of Ixodes ricinus ticks to higher altitudes in Slovakia. The discovery that our mountain study sites were a natural foci of B. lusitaniae was unexpected because this genospecies is usually associated with lizards and xerothermic habitats.

Environmental determinants ofIxodes ricinusticks and the incidence ofBorrelia burgdorferisensu lato, the agent of Lyme borreliosis, in Scotland

Lyme borreliosis (LB) is the most common arthropod-borne disease of humans in the Northern hemisphere. In Europe, the causative agent, Borrelia burgdorferi sensu lato complex, is principally vectored by Ixodes ricinus ticks. The aim of this study was to identify environmental factors influencing questing I. ricinus nymph abundance and B. burgdorferi s.l. infection in questing nymphs using a large-scale survey across Scotland. Ticks, host dung and vegetation were surveyed at 25 woodland sites, and climatic variables from a Geographical Information System (GIS) were extracted for each site. A total of 2397 10 m2 transect surveys were conducted and 13 250 I. ricinus nymphs counted. Questing nymphs were assayed for B. burgdorferi s.l. and the average infection prevalence was 5·6% (range 0·8-13·9%). More questing nymphs and higher incidence of B. burgdorferi s.l. infection were found in areas with higher deer abundance and in mixed/deciduous compared to coniferous forests, as well as weaker correlations with season, altitude, rainfall and ground vegetation. No correlation was found between nymph abundance and infection prevalence within the ranges encountered. An understanding of the environmental conditions associated with tick abundance and pathogen prevalence may be used to reduce risk of exposure and to predict future pathogen prevalence and distributions under environmental changes.

Presence, genetic variability, and potential significance of "Candidatus Midichloria mitochondrii" in the lone star tick Amblyomma americanum.

We used next generation sequencing to detect the bacterium "Candidatus Midichloria mitochondrii" for the first time in lone star ticks (Amblyomma americanum) from the eastern United States. 177 individuals and 11 tick pools from seven sites in four states were tested by pyrosequencing with barcoded 16S rRNA gene eubacterial primers targeting variable regions 5-3. Average infection prevalence was 0.15 across all surveyed populations (range 0-0.29) and only the site with the smallest sample size (n=5) was negative. Three genotypes differing by 2.6-4.1% in a 271bp region of 16S rRNA gene were identified. Two variants co-occurred in sites in North Carolina and New York, but were not observed in the same tick at those sites. The third genotype was found only in Georgia. Phylogenetic analysis of this fragment indicated that the three variants are more closely related to "Candidatus Midichloria mitochondrii" genotypes from other tick species than to each other. This variation suggests that multiple independent introductions occurred in A. americanum which may provide insight into bacterial spread within its ecosystem and parasitism on this tick. Whether the presence of this bacterium affects acquisition or maintenance of other pathogens and symbionts in A. americanum or the survival, biology and evolution of the tick itself is unknown.

A review on swimmer's itch and the occurrence of bird schistosomes in Iceland

In the past decade, swimmer's itch (SI) has repeatedly occurred in people who have been wading or bathing in ponds or lakes in Iceland where water birds and snails are abundant. Some of the affected sites were warmed by geothermal activity, and others were not. A search for the causative agent of SI, ocellate furcocercariae that have been found in Iceland only in Radix peregra snails, revealed an average infection prevalence of 1.4% (n = 12,432). Locally, infection rates commonly exceeded 6%, the highest value observed being 24.5%. A search for adult schistosomes in visceral organs and the nasal cavities of 110 water birds belonging to the orders Gaviiformes, Podicipediformes and Anseriformes revealed eggs, miracidia or adult stages of at least seven previously identifiable schistosome species in four anseriform bird species. A previously unknown species of schistosome, Allobilharzia visceralis, was detected in whooper swans (Cygnus cygnus), and classified in a new genus. In mallards (Anas platyrhynchos) a nasal Trichobilharzia sp. and the visceral schistosome T. franki were identified. In red-breasted merganser (Mergus serrator), distinct egg types belonging to two species of the genus Trichobilharzia have been found. In grey-lag goose (Anser anser) two different egg types were also found - a large Trichobilharzia sp. and small eggs of a Dendritobilharzia sp. Additionally, unidentified cercariae, probably belonging to a previously undescribed genus were detected in R. peregra in Oslandsstjörn. Taken together, the data obtained by morphological examination of eggs and recent DNA sequencing results, indicate that at least eight species of bird schistosomes occur in Iceland.