Showing papers in "Vector-borne and Zoonotic Diseases in 2011"

The emergence of Staphylococcus aureus ST398.

Abstract: The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) has changed dramatically over the past 15 years. Initially a nosocomial pathogen, newly emergent strains of MRSA have become increasingly common in the community among individuals lacking contact with healthcare. More recently, a third group of MRSA strains have been identified in association with livestock, particularly swine. These strains, termed livestock-associated MRSA, have now been identified in Europe, North America, and Asia in humans and animals. One molecular type, ST398, has been the dominant strain of livestock-associated MRSA identified to date. The emergence of this strain in animals and humans will be described in this review, including colonization and clinical infections caused by this strain. We also discuss lingering research questions and implications for controlling spread of this bacterium in an agricultural environment and beyond.

Dirofilarial infections in Europe.

Abstract: Nematodes of the genus Dirofilaria are currently considered emerging agents of parasitic zoonoses in Europe. Climatic changes and an increase in the movement of reservoirs (mostly infected dogs) have caused an increase in the geographical range of these parasites from the traditionally endemic/hyperendemic southern regions, and the risk for human infection has increased. In the last several years, forecast models have predicted that current summer temperatures are sufficient to facilitate extrinsic incubation of Dirofilaria in many areas of Europe. The global warming projected by the Intergovernmental Panel on Climate Change suggests that warm summers suitable for Dirofilaria transmission in Europe will be the rule in the future decades, and if the actual trend of temperature increase continues, filarial infection should spread into previously infection-free areas. Dirofilaria repens is currently the filarial species that is most commonly reported as spreading from southern to northern areas. This article reviews the zoonotic aspects, effects of climate, and other global drivers on Dirofilaria infections in Europe and the possible implications on the transmission and control of these mosquito-borne nematodes.

Worldwide distribution and diversity of seabird ticks: implications for the ecology and epidemiology of tick-borne pathogens.

Abstract: The ubiquity of ticks and their importance in the transmission of pathogens involved in human and livestock diseases are reflected by the growing number of studies focusing on tick ecology

Usutu virus in Africa.

Abstract: Usutu virus (USUV) was discovered in South Africa in 1959. Since then, it has been reported in several African countries including Senegal, Central African Republic, Nigeria, Uganda, Burkina Faso, Cote d'Ivoire, and Morocco. In 2001, USUV has been identified for the first time outside of Africa, namely in Europe, where it caused a significant mortality among blackbirds in Vienna, Austria. In 2009, the first two human cases of USUV infection in Europe have been reported in Italy, causing encephalitis in immunocompromised patients. The host range in Africa includes mainly Culex mosquitoes, birds, and also humans with one benign and one severe case. Given its role as a potential human pathogen and the similar appearance compared with other emerging arboviruses, it is essential to investigate the natural history and ecology of USUV in Africa. In this regard, we review the emergence of USUV in Africa, summarizing data about isolations, host range, and potential vectors, which should help to improve our understanding of the factors underlying the circulation of USUV in Europe and Africa.

Questing ticks in suburban forest are infected by at least six tick-borne pathogens.

Abstract: The role of Ixodes ricinus ticks in the transmission of pathogens of public health importance such as Borrelia burgdorferi s.l. is widely recognized and is suspected in several emerging vector-borne pathogens in Europe. Here, we assess prevalence rates of several endemic and emerging zoonotic pathogens in tick populations in an area of high human population density in France, to contribute to a risk assessment for potential transmission to humans. Pathogen prevalence rates were evaluated by polymerase chain reaction detection and sequencing in questing ticks, individually for adults and in pools of 10 for nymphs. In addition to finding micro-organisms corresponding to symbionts, we found high prevalence rates of B. burgdorferi s.l. (32% of adult females and 10% of nymphs) and low to moderate ones of Anaplasma phagocytophilum (∼1%), spotted fever group Rickettsia spp. (∼6%), Babesia sp. EU1 (∼1%), Bartonella birtlesii (0.1%), and Francisella tularensis (∼1%). Our findings extend the knowledge of t...

Tick surveillance in Great Britain.

Abstract: The ability for public/veterinary health agencies to assess the risks posed by tick-borne pathogens is reliant on an understanding of the main tick vector species. Crucially, the status, distribution, and changing trends in tick distribution and abundance are implicit requirements of any risk assessment; however, this is contingent on the quality of tick distribution data. Since 2005 the Health Protection Agency has promoted an enhanced tick surveillance program. Through engagement with a variety of public and veterinary health agencies and practitioners (e.g., clinicians and veterinarians), wildlife groups (deer society, zoos, animal refuge centers, and academics), and amateur entomologists, >4000 ticks from 900 separate records across Great Britain have been submitted, representing 14 tick species (Ixodes ricinus, Ixodes hexagonus, Ixodes acuminatus, Ixodes arboricola, Ixodes canisuga, Ixodes frontalis, Ixodes lividus, Ixodes trianguliceps, Ixodes ventalloi, Carios vespertilionis, Dermacentor reticulatus, Haemaphysalis punctata, Hyalomma marginatum, and Amblyomma species). The majority of ticks submitted were I. ricinus (81%), followed by I. hexagonus (10%) and I. frontalis (2.5%). Predominant host groups include companion animals (411 records), humans (198 records), wild birds (111 records), and large wild mammals (88 records), with records also from small/medium wild mammals, livestock, the environment and domestic/aviary birds. The scheme has elucidated the detection of two nonnative tick species, the expansion of previously geographically restricted D. reticulatus and produced ground data on the spread of I. ricinus in southwest England. It has also provided a forum for submission of ticks from the concerned public and particularly those infected with Lyme borreliosis, thus raising awareness among public health agencies of the increased peri-urban tick problem in Britain. Our results demonstrate that it is possible to run a cost-effective nationwide surveillance program to successfully monitor endemic tick species, identify subtle changes in their distribution, and detect the arrival and presence of exotic species.

Rodents as sentinels for the prevalence of tick-borne encephalitis virus.

Abstract: Introduction: Tick-borne encephalitis virus (TBEV) causes one of the most important flavivirus infections of the central nervous system, affecting humans in Europe and Asia. It is mainly transmitted by the bite of an infected tick and circulates among them and their vertebrate hosts. Until now, TBE risk analysis in Germany has been based on the incidence of human cases. Because of an increasing vaccination rate, this approach might be misleading, especially in regions of low virus circulation. Method: To test the suitability of rodents as a surrogate marker for virus spread, laboratory-bred Microtus arvalis voles were experimentally infected with TBEV and analyzed over a period of 100 days by real-time (RT)–quantitative polymerase chain reaction. Further, the prevalence of TBEV in rodents trapped in Brandenburg, a rural federal state in northeastern Germany with autochthonous TBE cases, was determined and compared with that in rodents from German TBE risk areas as well as TBE nonrisk areas. Resul...

Infrequency of Rickettsia rickettsii in Dermacentor variabilis removed from humans, with comments on the role of other human-biting ticks associated with spotted fever group Rickettsiae in the United States.

Abstract: From 1997 to 2009, the Tick-Borne Disease Laboratory of the U.S. Army Public Health Command (USAPHC) (formerly the U.S. Army Center for Health Promotion and Preventive Medicine) screened 5286 Dermacentor variabilis ticks removed from Department of Defense (DOD) personnel, their dependents, and DOD civilian personnel for spotted fever group rickettsiae using polymerase chain reaction and restriction fragment length polymorphism analysis. Rickettsia montanensis (171/5286 = 3.2%) and Rickettsia amblyommii (7/5286 = 0.1%) were detected in a small number of samples, but no ticks were found positive for Rickettsia rickettsii, the agent of Rocky Mountain spotted fever (RMSF) until May 2009, when it was detected in one D. variabilis male removed from a child in Maryland. This result was confirmed by nucleotide sequence analysis of the rickettsial isolate and of the positive control used in the polymerase chain reaction, which was different from the isolate. Lethal effects of rickettsiostatic proteins of ...

Culex Flavivirus and West Nile Virus Mosquito Coinfection and Positive Ecological Association in Chicago, United States

Abstract: Culex flavivirus (CxFV) is an insect-specific flavivirus globally distributed in mosquitoes of the genus Culex. CxFV was positively associated with West Nile virus (WNV) infection in a case-control study of 268 mosquito pools from an endemic focus of WNV transmission in Chicago, United States. Specifically, WNV-positive Culex mosquito pools were four times more likely also to be infected with CxFV than were spatiotemporally matched WNV-negative pools. In addition, mosquito pools from residential sites characterized by dense housing and impermeable surfaces were more likely to be infected with CxFV than were pools from nearby urban green spaces. Further, 6/15 (40%) WNV-positive individual mosquitoes were also CxFV positive, demonstrating that both viruses can coinfect mosquitoes in nature. Phylogenetic analysis of CxFV from Chicago demonstrated a pattern similar to WNV, consisting of low global viral diversity and lack of geographic clustering. These results illustrate a positive ecological association between CxFV and WNV, and that coinfection of individual mosquitoes can occur naturally in areas of high flaviviral transmission. These conclusions represent a challenge to the hypothesis of super-infection exclusion in the CxFV/WNV system, whereby an established infection with one virus may interfere with secondary viral infection with a similar virus. This study suggests that infection with insect-specific flaviviruses such as CxFV may not exclude secondary infection with genetically distinct flaviviruses such as WNV, and that both viruses can naturally coinfect mosquitoes that are epidemic bridge vectors of WNV to humans.

First Molecular Evidence of Anaplasma ovis and Rickettsia spp. in Keds (Diptera: Hippoboscidae) of Sheep and Wild Ruminants

Abstract: To evaluate the presence of rickettsial agents in hippoboscid flies with molecular methods, 81 sheep keds (Melophagus ovinus) were collected from 23 sheep, 144 deer keds (Lipoptena cervi) were caught in the environment, and a further 463 and 59 individuals of the latter species were obtained from fresh carcasses of 29 red deer and 17 roe deer, respectively. DNA was extracted individually or in pools. Anaplasma ovis was demonstrated in all examined sheep keds, and from one pool of free-living deer keds. Rickettsia helvetica or other, unidentified rickettsiae were also present in one pool of sheep keds, and in four pools of deer keds from both red deer and roe deer. This is the first account of polymerase chain reaction positivity of hippoboscid flies for A. ovis and rickettsiae. These results raise the possibility that-apart from cattle and roe deer as already reported-sheep and red deer might also play a reservoir role in the epidemiology of rickettsioses.

Experimental infection of Rhipicephalus sanguineus ticks with the bacterium Rickettsia rickettsii, using experimentally infected dogs.

Abstract: We evaluated if Rickettsia rickettsii-experimentally infected dogs could serve as amplifier hosts for hipicephalus sanguineus ticks. In addition, we checked if Rh. sanguineus ticks that acquired Ri. rickettsii from dogs could transmit the bacterium to susceptible hosts (vector competence), and if these ticks could maintain the bacterium by transstadial and transovarial transmissions. Uninfected larvae, nymphs, and adults of Rh. sanguineus were allowed to feed upon three groups of dogs: groups 1 (G1) and 2 (G2) composed of Ri. rickettsii-infected dogs, infected intraperitoneally and via tick bites, respectively, and group 3 composed of uninfected dogs. After larval and nymphal feeding on rickettsemic dogs, 7.1-15.2% and 35.8-37.9% of the molted nymphs and adults, respectively, were shown by polymerase chain reaction (PCR) to be infected by Ri. rickettsii, confirming that both G1 and G2 dogs were efficient sources of rickettsial infection (amplifier host), resulting in transstadial transmission of the agent. These infected nymphs and adults successfully transmitted Ri. rickettsii to guinea pigs, confirming vector competence after acquisition of the infection from rickettsemic dogs. Transovarial transmission of Ri. rickettsii was observed in engorged females that had been infected as nymphs by feeding on both G1 and G2 dogs, but not in engorged females that acquired the infection during adult feeding on these same dogs. In the first case, filial infection rates were generally <50%. No tick exposed to G3 dogs was infected by rickettsiae in this study. No substantial mortality difference was observed between Ri. rickettsii-infected tick groups (G1 and G2) and uninfected tick group (G3). Our results indicate that dogs can be amplifier hosts of Ri. rickettsii for Rh. sanguineus, although only a minority of immature ticks (<45%) should become infected. It appears that Rh. sanguineus, in the absence of horizontal transmission, would not maintain Ri. rickettsii through successive generations, possibly because of low filial infection rates.

Detection of Usutu Virus Within a West Nile Virus Surveillance Program in Northern Italy

Abstract: Usutu virus (USUV) is a mosquito-borne flavivirus belonging to the Japanese encephalitis serocomplex, recently related to neurological disease in immunosuppressed patients. In the same area of Northern Italy where USUV human cases occurred in 2009, a regional West Nile virus (WNV) surveillance program based on mosquito monitoring and wild birds screening has been implemented since 2008. Mosquito pools and wild birds were tested using three different polymerase chain reactions (Flavivirus, WNV, and USUV). During summer 2009, 56 pools (54 consisting of Culex pipiens and 2 of Aedes albopictus) and 27 pools (Cx. pipiens) out of 1789 mosquito pools were, respectively, USUV and WNV positive. Moreover, out of 1218 wild birds tested, 44 were WNV positive, whereas only 11 birds were USUV positive by polymerase chain reaction. Data collected during 2009 prove a cocirculation of USUV and WNV in Northern Italy, but these two viruses show different incidence values in both mosquitoes and birds, suggesting inv...

Investigation of the ecology of Francisella tularensis during an inter-epizootic period.

Abstract: A 1-year study of the ecological cycle of Francisella tularensis was performed in an enzootic area during an inter-epizootic period. The study was based on multiple sampling of all major constituents of the disease cycle. Seroprevalence of tularemia in the European brown hare (Lepus europaeus) population was 5.1% (10/197) with low antibody titers (1/10 and 1/20), and F. tularensis ssp. holarctica was isolated from four hares. F. tularensis was not detected in the 38 common voles (Microtus arvalis), 110 yellow-necked mice (Apodemus flavicollis), or 15 stripped field mice (Apodemus agrarius) trapped during the study, or the by-catch of 8 Eurasian pygmy shrews (Sorex minutus) or 6 common shrews (Sorex araneus). A total of 1106 Ixodes ricinus and 476 Haemaphysalis concinna ticks were collected from vegetation, and 404 I. ricinus, 28 H. concinna ticks, and 15 Ctenophtalmus assimilis and 10 Nosopsyllus fasciatus fleas were combed off small mammals. One H. concinna female and one nymph collected from the vegetation was found infected with F. tularensis ssp. holarctica by TaqMan polymerase chain reaction, thus resulting a 0.42% (2/476) prevalence. F. tularensis-specific DNA was not detected in environmental water samples, and the examined 100 sheep, 50 cows, and 50 buffalos grazed at the study area were all seronegative. During inter-epizootic periods, F. tularensis ssp. holarctica seems to persist only in the European brown hare--H. concinna cycle at the studied habitat. H. concinna may not serve exclusively as an arthropod vector, but it may also harbor bacteria for 3-4 years through multiple life stages and act as an important reservoir of F. tularensis. Rodent species probably do not serve as true reservoir hosts of tularemia.

Molecular Epidemiological Investigation of Plasmodium knowlesi in Humans and Macaques in Singapore

Abstract: Singapore reported its first locally acquired human Plasmodium knowlesi infection in 2007, involving a soldier who had undergone training in a forested area where long-tailed macaques are frequently seen. Comprehensive disease surveillance and monitoring system that was set up after the initial case detected four additional human P. knowlesi cases in 2007 and one in 2008. All involved military personnel who had undergone training in the forested area, and none had traveled out of Singapore 1 month before the onset of symptoms. Screening for malaria parasites on blood obtained from long-tailed macaques revealed that wild monkeys (n = 3) caught from the forested area were infected with P. knowlesi, whereas peri-domestic monkeys (n = 10) caught from a nature reserve park were not infected with any malaria parasites. Phylogenetic analysis of the nonrepeat region of the P. knowlesi csp genes showed that the sequences obtained from the human cases were not distinct from those obtained from wild monkeys...

Larval Environmental Temperature and Insecticide Exposure Alter Aedes aegypti Competence for Arboviruses

Abstract: Temperature is a key factor influencing mosquito growth and development and is also known to affect insecticide efficacy. We evaluated the effects of larval rearing temperature and exposure to insecticides on adult mosquito fitness and competence for arboviral infection using Sindbis virus (SINV). We exposed newly hatched larvae of Aedes aegypti to an environmentally realistic level of insecticide malathion at 20°C and 30°C and allowed the resulting adults to feed on SINV-infected blood meal. Exposure to malathion significantly reduced survival to adulthood. Statistically significant interactions between temperature and malathion were observed for body size, estimated population growth, and SINV infection and dissemination. Malathion-exposed Ae. aegypti cohorts had significantly higher population growth at 20°C than at 30°C. Body size decreased with higher temperature and malathion-exposed females were larger than unexposed females at 20°C but not at 30°C. Viral infection and dissemination increa...

The Status of Rift Valley Fever in Animals in Saudi Arabia: A Mini Review

Abstract: In August-September 2000, an overwhelming outbreak of Rift Valley fever (RVF) struck the southwestern part of Saudi Arabia and adjoining Yemeni territories. During the outbreak, which was the first ever to be recorded outside Africa, around 40,000 animals, mostly sheep and goats, died or aborted and 883 cases, with 124 deaths, were recorded among humans in Saudi Arabia. An additional 1328 human cases, with 166 deaths, were concurrently recorded in northwestern Yemen. Vector studies in Saudi Arabia established Aedes vexans arabiensis and Culex (culex) triteniorynchus as the biological vectors of RVF virus in the region. Both of these species and several others, which could be potential vectors of the virus, occur throughout the Kingdom. Rigorous control measures were implemented, which succeeded in curtailing the infection and preventing its spread to other parts of the country. However, the virus persisted in a cryptic form in the original area of the epizootic, resulting in intermittent diagnosis of few cases throughout the past 10 years. To date, however, no evidence was found of virus activity outside that area. This review provides, from a veterinary perspective, a brief account of the events surrounding the epizootic and its present status in Saudi Arabia and emphasizes the need for vigilance, preparedness, and regular monitoring of the disease by serosurveillance methods.

High Rates of Rickettsia parkeri Infection in Gulf Coast Ticks (Amblyomma maculatum) and Identification of “Candidatus Rickettsia Andeanae” from Fairfax County, Virginia

Abstract: The Gulf Coast tick, Amblyomma maculatum, is a vector of Rickettsia parkeri, a recently identified human pathogen that causes a disease with clinical symptoms that resemble a mild form of Rocky Mountain spotted fever. Because the prevalence of R. parkeri infection in geographically distinct populations of A. maculatum is not fully understood, A. maculatum specimens collected as part of a tick and pathogen surveillance system in Fairfax County, Virginia, were screened to determine pathogen infection rates. Overall, R. parkeri was found in 41.4% of the A. maculatum that were screened. Additionally, the novel spotted fever group Rickettsia sp., tentatively named "Candidatus Rickettsia andeanae," was observed for the first time in Virginia.

A serological and molecular study of Leishmania infantum infection in cats from the Island of Ibiza (Spain).

Abstract: The aim of this study was to evaluate the prevalence of Leishmania infantum infection within a feline population by serologic and molecular methods and to identify associated risk factors. One hundred five cats living outdoors were studied. Sera were tested for IgG antibodies against L. infantum, Toxoplasma gondii, and feline immunodeficiency virus (FIV) and for the detection of feline leukemia virus (FeLV) p27 antigen by enzyme-linked immunosorbent assay (ELISA). L. infantum real-time polymerase chain reaction (PCR) was performed on DNA extracted from blood. L. infantum and T. gondii seroprevalence rates were 13.2% and 55.2%, respectively. The prevalence of L. infantum by PCR was 8.7%. The total rate of L. infantum infection derived from seroreactivity and/or positive PCR was 15.4%. Serology and PCR results were positively associated, and moderate agreement (kappa = 0.489) was found between Leishmania ELISA and PCR. No statistical association was found between positive Leishmania PCR results and...

Pilot study assessing the effectiveness of long-lasting permethrin-impregnated clothing for the prevention of tick bites.

Abstract: Introduction: Tick-borne diseases such as Lyme disease, Rocky Mountain spotted fever, and ehrlichiosis are a significant concern for many thousands of workers who have frequent and unavoidable exposure to tick-infested habitats. Many North Carolina state employees with outdoor occupations report multiple tick bites each year, indicating that existing tick preventive strategies may be underutilized or ineffective. Treatment of clothing with permethrin, a nontoxic chemical with insecticidal, knockdown, and repellent properties, is highly effective against ticks. However, most permethrin products must be reapplied after several washings to maintain insecticidal activity. Recently, a factory-based method for long-lasting permethrin impregnation of clothing has been developed by Insect Shield, Inc., that allows clothing to retain insecticidal activity for over 70 washes. Methods: A nonrandomized open label pilot study was conducted to determine the effectiveness of Insect Shield–treated clothing for t...

Unexpected anthropophily in the potential secondary malaria vectors Anopheles coustani s.l. and Anopheles squamosus in Macha, Zambia.

Abstract: Anopheles coustani s.l. and Anopheles squamosus are sub-Saharan mosquito species that have been implicated in malaria transmission. Although generally believed to be of negligible importance due to their overwhelmingly zoophilic behavior, An. coustani s.l. and An. squamosus made up a large proportion of the anophelines collected by human landing catches during the 2007-2008 and 2008-2009 rainy seasons in Macha, Zambia. Further, polymerase chain reaction-based blood meal identification showed that the majority of blood meals from these mosquito species caught in human-baited Centers for Disease Control light traps were from human hosts. Although no An. coustani s.l. or An. squamosus were found to be positive for Plasmodium, the demonstrated anthropophilic tendencies of these mosquitoes in southern Zambia suggest their potential as secondary malaria vectors.

Genetic Variants of Anaplasma phagocytophilum in Wild Caprine and Cervid Ungulates from the Alps in Tyrol, Austria

Abstract: The occurrence of genetic variants of Anaplasma phagocytophilum was studied in wild ungulates from the northern and central eastern Alps in Tyrol, Austria. For this purpose, spleen samples collected from 53 game animals during the hunting season 2008/2009 (16 roe deer [Capreolus capreolus], 10 red deer [Cervus elaphus], 16 Alpine chamois [Rupicapra r. rupicapra], 7 Alpine ibex [Capra i. ibex], and 4 European mouflons [Ovis orientalis musimon]) were analyzed. Thirty-five animals originated from the Karwendel mountains, 12 from the Kaunertal area (Otztal Alps), and the remaining from other mountainous areas in Tyrol. DNA extracts were screened with a real-time polymerase chain reaction targeting the msp2 gene of A. phagocytophilum. A total of 23 (43.4%) samples, from all ungulate species studied, were A. phagocytophilum positive. As of the date of this article, A. phagocytophilum has not been reported in the Alpine ibex. The positive samples were investigated further with polymerase chain reactions for amplification of the partial 16S rRNA, groEL, and msp4 genes. Sequence analysis using forward and reverse primers revealed seven different 16S rRNA gene variants. No variant could be attributed to any particular ungulate species. The groEL gene revealed 11 different variants, which grouped in the phylogenetic analysis into two distinct clusters: one cluster contained the sequences from roe deer, whereas the sequences of the other species formed the second cluster. The msp4 gene showed a high degree of variability in the amplified part with a total of 10 different sequence types. The results show that the wild mountain ungulates were infected to a considerable extent with various variants of A. phagocytophilum. The pathogenicity of the variants and the reservoir competence of the species investigated in this study deserve further attention in future studies.

Prevalence of Rift Valley Fever Infection in Ruminants in Madagascar After the 2008 Outbreak

Abstract: A Rift Valley fever (RVF) outbreak occurred in Madagascar from January to May 2008. The objectives of this study were (1) to assess the current and past circulation of RVF virus (RVFV) in livestock in Madagascar and (2) to evaluate the extent and magnitude of the 2008 RVF outbreak in livestock. The results of a country-wide serosurvey conducted in August 2008 on small and large ruminants are reported here. The study included 3437 cattle and 989 small ruminants (227 sheep and 762 goats) sampled in 30 of the 111 Malagasy districts, selected to be representative of the different ecozones and livestock density areas. Sera of animals were tested for the detection of immunoglobulins M (IgM) and G (IgG) against RVFV using commercial enzyme-linked immunosorbent assays kits. Recent infections (presence of IgM against RVFV) were detected in only 9 cattle (0.3% [0.1-0.4]) and 33 small ruminant (3.3% [2.2-4.5]) samples. Past infections (presence of IgG and absence of IgM against RVFV) were detected in 887 cattle (25.8% [24.3-27.3]) and 244 small ruminant (24.7% [22.0-27.4]) samples. Past infections were detected in all sampled sites. All ecozones were affected. In the southern and northwestern areas, the prevalence of cattle showing evidence of past infection with RVFV increased with the age of the animals. Our results suggest that there has been country-wide circulation of RVFV in 2008 in Madagascar, including in parts of the country where no clinical illness, either in animals or in humans, was reported. The data also suggest that the southern and northwestern areas may be endemic for RVFV, and that the virus may spread when ecological conditions are favorable for its amplification.

Geographic and Temporal Variations in Population Dynamics of Ixodes ricinus and Associated Borrelia Infections in The Netherlands

Abstract: In a countrywide investigation of the ecological factors that contribute to Lyme borreliosis risk, a longitudinal study on population dynamics of the sheep tick Ixodes ricinus and their infections with Borrelia burgdorferi sensu lato (s.l.) was undertaken at 24 sites in The Netherlands from July 2006 to December 2007. Study sites were mature forests, dune vegetations, or new forests on land reclaimed from the sea. Ticks were sampled monthly and nymphal ticks were investigated for the presence of Borrelia spp. I. ricinus was the only tick species found. Ticks were found in all sites, but with significant spatial and temporal variations in density between sites. Peak densities were found in July and August, with lowest tick numbers collected in December and January. In some sites, questing activities of I. ricinus nymphs and adults were observed in the winter months. Mean monthly Borrelia infections in nymphs varied from 0% to 29.0% (range: 0%-60%), and several sites had significantly higher mean nymphal Borrelia infections than others. Four genospecies of Borrelia burgdorferi s.l. were found, with B. afzelii being dominant at most sites. Borrelia infection rates in nymphal ticks collected in July, September, and November 2006 were significantly higher (23.7%, p<0.01) than those in the corresponding months of 2007 (9.9%). The diversity in Borrelia genospecies between sites was significantly different (p<0.001). Habitat structure (tree cover) was an effective discriminant parameter in the determination of Borrelia infection risk, as measured by the proportion of nymphal ticks infected with B. burgdorferi s.l. Thickness of the litter layer and moss cover were positively related to nymphal and adult tick densities. The study shows that Borrelia-infected ticks are present in many forest and dune areas in The Netherlands and suggests that in such biotopes, which are used for a wide variety of recreational activities, the infection risk is high.

Rickettsia spp. in wild small mammals in Lower Bavaria, South-Eastern Germany.

Abstract: So far, data on the natural cycle of rickettsiae of the tick-borne spotted fever group (SFG) in Central Europe are barely available. Some studies showed the occurrence of different Rickett...

Borrelia burgdorferi has minimal impact on the Lyme disease reservoir host Peromyscus leucopus.

Abstract: The epidemiology of vector-borne zoonotic diseases is determined by encounter rates between vectors and hosts. Alterations to the behavior of reservoir hosts caused by the infectious agent have the potential to dramatically alter disease transmission and human risk. We examined the effect of Borrelia burgdorferi, the etiological agent of Lyme disease, on one of its most important reservoir hosts, the white-footed mouse, Peromyscus leucopus. We mimic natural infections in mice using the vector (Black-legged ticks, Ixodes scapularis) and examine the immunological and behavioral responses of mouse hosts. Despite producing antibodies against B. burgdorferi, infected mice did not have elevated white blood cells compared with uninfected mice. In addition, infected and uninfected mice did not differ in their wheel-running activity. Our results suggest that infection with the spirochete B. burgdorferi has little impact on the field activity of white-footed mice. Lyme disease transmission appears to be uncomplicated by pathogen-altered behavior of this reservoir host.

New genetic variants of Anaplasma phagocytophilum and Anaplasma bovis from Korean water deer (Hydropotes inermis argyropus).

Abstract: Wild deer are one of the important natural reservoir hosts of Anaplasma species, which cause granulocytic anaplasmosis in equines, canines, and humans. The objective of the present study w...

First serological evidence of West Nile virus activity in horses in Serbia.

Abstract: West Nile virus (WNV), the most widely distributed flavivirus worldwide, has lately reemerged in Europe, causing worrisome outbreaks in humans and horses. Serological analysis by enzyme-linked immunoassay and plaque reduction neutralization test showed for the first time in Serbia that 12% of 349 horses presented specific neutralizing WNV antibodies, which in one case also cross-neutralized Usutu virus (USUV). This is the first time that anti-USUV high neutralizing antibody titers are reported in horses. All these data indicate that WNV and USUV are circulating in the region and advise on the convenience of implementing surveillance programs.

Mapping the current distribution and predicted spread of the leishmaniosis sand fly vector in the madrid region (Spain) based on environmental variables and expected climate change.

Abstract: Leishmaniosis caused by Leishmania infantum is a widespread zoonotic disease that is endemic in the Mediterranean basin. Based on prior point abundance data for the two sand fly vectors of leishmaniosis in the Madrid region (Phlebotomus perniciosus and Phlebotomus ariasi), models were constructed to predict the spatial distribution patterns of these vectors. The models were obtained by negative binomial regression of several environmental variables and then used to map vector distributions. To validate the maps, we used serological prevalence data of Leishmania infection in dogs and incidence data were obtained through questionnaires completed by veterinarians in the region. Seropositive dogs and veterinary clinics registering a higher incidence of canine leishmaniosis appeared closer to our modeled vector foci. In the face of climate change, we simulated the future distributions of the sand flies for each third of the 21st century and predicted their spread in the region.

First report of the isolation and molecular characterization of Rickettsia amblyommii and Rickettsia felis in Central America.

Abstract: During 2010, 15 adult ticks, identified as Amblyomma cajennense, were collected from horses in Cahuita and Turrialba districts, whereas 7 fleas, identified as Ctenocephalides felis, were collected from a dog in San Jose city, Costa Rica. In the laboratory, three A. cajennense specimens, two from Cahuita and one from Turrialba, were individually processed for rickettsial isolation in cell culture, as was a pool of seven fleas. Rickettsiae were successfully isolated and established in Vero cell culture from the three ticks and from a pool of seven fleas in C6/36 cell culture. The three tick isolates were genotypically identified as Rickettsia amblyommii, and the flea isolate was identified as Rickettsia felis through DNA sequencing of portions of the rickettsial genes gltA, ompA, and ompB of each isolate. In addition, other seven ticks were shown to contain rickettsial DNA. Polymerase chain reaction products of at least two of these ticks were sequenced and also showed to correspond to R. amblyommi...

Leishmaniasis in an Era of Conflict in the Middle East

Abstract: Leishmaniasis is endemic in the Middle East, and both cutaneous and visceral forms are reported from the region ranging from the Levant to Afghanistan. The potential and proven phlebotomine sand fly vectors and reservoir hosts of the Leishmaniases species in Afghanistan, Iran, Iraq, Israel, Jordan, Lebanon, Saudi Arabia, Syria, Turkey, and Yemen are described. This region has seen a movement of populations across the area, due to both military and civilian strife. Refugees, armed forces, and multi-national contractors are particularly at risk to acquire this disease. There has been an upsurge in Leishmaniasis research, especially as new foci are exposed and the need to protect the naive populations moving into endemic areas becomes a public health priority. New sand fly vectors and animal reservoirs have been discovered while novel control methods are being evaluated. Modern molecular techniques are now being used more routinely and revealing some unusual findings. The aim of this review is to collate the most recent data on the burden of the disease, diagnostic applications, eco-epidemiology of vectors, and reservoir hosts, and how the control projects have been developing in the Middle East.