Vector-borne diseases in horses are illnesses transmitted by vectors such as mosquitoes, ticks, and flies. These diseases can affect equine health by introducing pathogens like viruses, bacteria, or parasites into the horse's system. Common vector-borne diseases in horses include West Nile Virus, Equine Infectious Anemia, and Lyme disease. The transmission dynamics, clinical manifestations, and management strategies for these diseases vary depending on the pathogen and vector involved. Understanding these aspects is important for developing preventive measures and treatment protocols. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, and management of vector-borne diseases in equines.
Pauvolid-Corrêa A, Tavares FN, Costa EV, Burlandy FM, Murta M, Pellegrin AO, Nogueira MF, Silva EE.As in humans, sub-clinical infection by arboviruses in domestic animals is common; however, its detection only occurs during epizootics and the silent circulation of some arboviruses may remain undetected. The objective of the present paper was to assess the current circulation of arboviruses in the Nhecolândia sub-region of South Pantanal, Brazil. Sera from a total of 135 horses, of which 75 were immunized with bivalent vaccine composed of inactive Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus(WEEV) and 60 were unvaccinated, were submitted to thorough viral i...
Muzari MO, Burgess GW, Skerratt LF, Jones RE, Duran TL.Tabanid flies in Australia are potential vectors of the parasite Trypanosoma evansi which causes the animal disease surra. It is endemic to most of south-east Asia and could enter Australia, but evaluation of the potential impact of a surra incursion requires identification of the major hosts of Australian tabanids. This study investigated the natural pattern of feeding and host preference by tabanid flies of Townsville, north Queensland by identification of ingested blood in trap-caught tabanids using ELISA. The assays were developed for identification of horse, cow, macropod and pig blood me...
Arrigo NC, Adams AP, Watts DM, Newman PC, Weaver SC.Eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) is an arbovirus that causes severe disease in humans in North America and in equids throughout the Americas. The enzootic transmission cycle of EEEV in North America involves passerine birds and the ornithophilic mosquito vector, Culiseta melanura, in freshwater swamp habitats. However, the ecology of EEEV in South America is not well understood. Culex (Melanoconion) spp. mosquitoes are considered the principal vectors in Central and South America; however, a primary vertebrate host for EEEV in South America has not...
Roth D, Henry B, Mak S, Fraser M, Taylor M, Li M, Cooper K, Furnell A, Wong Q, Morshed M.In 2009, an expansion of West Nile virus (WNV) into the Canadian province of British Columbia was detected. Two locally acquired cases of infection in humans and 3 cases of infection in horses were detected by ELISA and plaque-reduction neutralization tests. Ten positive mosquito pools were detected by reverse transcription PCR. Most WNV activity in British Columbia in 2009 occurred in the hot and dry southern Okanagan Valley. Virus establishment and amplification in this region was likely facilitated by above average nightly temperatures and a rapid accumulation of degree-days in late summer....
Freitas MC, Grycajuk M, Molento MB, Bonacin J, Labruna MB, Pacheco Rde C, Moraes-Filho J, Deconto I, Biondo AW.Brazilian Spotted Fever (BSF) is an often fatal zoonosis caused by the obligate intracellular bacterium Rickettsia rickettsii. The disease is generally transmitted to humans by Amblyomma spp. ticks. Serological evidence of past infection by R. rickettsii has been reported in horses, but the pathogenicity of R. rickettsii in horses remains unknown. Cart horses are still widely used in urban and urban fringe areas in Brazil, and these animals may constitute suitable sentinels for BSF human in these areas, for example, in Sao Jose dos Pinhais, where the first BSF human case in the state of Parana...
Phoutrides E, Jusino-Mendez T, Perez-Medina T, Seda-Lozada R, Garcia-Negron M, Davila-Toro F, Hunsperger E.After the isolation of West Nile virus (WNV) from humans, mosquitoes, and chickens in 2007, an analysis of animal surveillance involving multiple species (horses, monkeys, sheep, dogs, and birds) used to track WNV transmission from 2006 to 2008 was performed. During this period 13.4% of all the animal samples collected were seropositive by blocking ELISA for WNV. The most complete island-wide sampling was obtained from horses of which 22% were serologically positive and 96% were confirmed as WNV infections by plaque-reduction neutralization test. Our conclusion from this 3-year study is that a...
Deardorff ER, Weaver SC.The mosquito Culex (Melanoconion) taeniopus is a proven vector of enzootic Venezuelan equine encephalitis virus (VEEV) subtype IE in Central America. It has been shown to be highly susceptible to infection by this subtype, and conversely to be highly refractory to infection by other VEEV subtypes. During the 1990s in southern coastal Mexico, two VEE epizootics in horses were attributed to subtype IE VEEV. These outbreaks were associated with VEEV strains with an altered infection phenotype for the epizootic mosquito vector, Aedes (Ochlerotatus) taeniorhynchus. To determine the infectivity for ...
Zimmerli U, Herholz C, Schwermer H, Hofmann M, Griot C.African horse sickness (AHS) of equines is partly transmitted by the same culicoides species as Bluetongue (BT) disease in even-toed ungulates. Horses normally get seriously sick, with a high case fatality rate. Equine Encephalosis is another, but less-known viral disease of equines, caused by viruses of the same genus as BT and AHS. Like BT of serotype 8 in 2006, both diseases could theoretically be introduced to Europe anytime and spread rapidly then. After the lessons learnt from the most recent bluetongue outbreaks in Europe, the regulations and AHS-contingency plans in force must be updat...
Chevalier V, Dupressoir A, Tran A, Diop OM, Gottland C, Diallo M, Etter E, Ndiaye M, Grosbois V, Dia M, Gaidet N, Sall AA, Soti V, Niang M.In 2005, a serological study was carried out on horses in five ecologically contrasted zones of the Senegal River basin (Senegal) to assess West Nile virus (WNV) transmission and investigate underlying environmental risk factors. In each study zone, horses were randomly selected and blood samples taken. A land-cover map of the five study areas was built using two satellite ETM+ images. Blood samples were screened by ELISA for anti-WNV IgM and IgG and positive samples were confirmed by seroneutralization. Environmental data were analysed using a principal components analysis. The overall IgG se...
Maclachlan NJ, Guthrie AJ.Arthropod-transmitted viruses (Arboviruses) are important causes of disease in humans and animals, and it is proposed that climate change will increase the distribution and severity of arboviral diseases. Orbiviruses are the cause of important and apparently emerging arboviral diseases of livestock, including bluetongue virus (BTV), African horse sickness virus (AHSV), equine encephalosis virus (EEV), and epizootic hemorrhagic disease virus (EHDV) that are all transmitted by haematophagous Culicoides insects. Recent changes in the global distribution and nature of BTV infection have been espec...
Kalinová Z, Cisláková L, Halánová M.Ehrlichiosis and anaplasmosis are zoonoses caused by bacteria from the family Anaplasmataceae, including human and animal pathogens. The human pathogens are Ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (HME), Anaplasma phagocytophilum, the pathogen causing human granulocytic anaplasmosis (HGA), E. ewingii and Neorickettsia sennetsu, granulocytotropic and monocytotropic Ehrlichia species, respectively. Ehrlichia spp. are small, gram-negative, obligate intracellular bacteria. They replicate in the cytoplasmic vacuoles of host cells, especially granulocytes and monoc...
Papadopoulos E, Rowlinson M, Bartram D, Carpenter S, Mellor P, Wall R.An in vitro assay was used to assess the efficacy of the proprietary pyrethroid insecticide cypermethrin applied to horses (Deosect spray, 5.0%, w/v Fort Dodge Animal Health) against the biting midge Culicoides nubeculosus (Meigen) (Diptera: Ceratopogonidae) and the mosquitoes Aedes aegypti Linneaus and Culex quinquefasciatus Say (Diptera: Culicidae). Hair was collected from the back, belly and legs of the horses immediately prior to treatment and 7, 14, 21, 28 and 35 days after treatment, and also from untreated controls. In laboratory assays groups of 10 adult female C. nubeculosus, Ae. aegy...
Zoonoses and public healthDecember 23, 2009
Volume 57, Issue 3 211-219 doi: 10.1111/j.1863-2378.2009.01303.x
Calistri P, Giovannini A, Savini G, Monaco F, Bonfanti L, Ceolin C, Terregino C, Tamba M, Cordioli P, Lelli R.After 10 years, West Nile virus (WNV) re-emerged in Italy in August 2008. As on 31 December 2008, the infection affected eight Provinces in three Regions (Emilia Romagna, Veneto, Lombardy), where a total of 794 cases of WNV infection in 251 equine stables were detected on the basis of the clinical signs and as a result of a serological screening in horses living in the area. Only 4.0% (32/794) of the serologically positive animals showed clinical signs, and the 32 clinical cases were reported in 18 different farms. The observed case-fatality rate was 15.6% (5/32). The confirmed clinical cases ...
Maurizi L, Marié JL, Aoun O, Courtin C, Gorsane S, Chal D, Davoust B.A precise assessment of the epidemiological extent of equine Lyme disease is not well established in metropolitan France, French Guiana, and Africa (Chad, Djibouti, Ivory Coast, Gabon, and Democratic Republic of Congo). Blood samples were obtained from 570 horses. The samples were tested for Borrelia burgdorferi infection by a commercial ELISA Dot-Blot method (SNAP 4 Dx; IDEXX S. Laboratory). Lyme disease antibodies were only detected in metropolitan France, specifically in the eastern and center-western regions (48% and 31%). The geographical distribution of the disease follows the distributi...
Woldehiwet Z.Anaplasma phagocytophilum is the recently designated name replacing three species of granulocytic bacteria, Ehrlichia phagocytophila, Ehrlichia equi and the agent of human granulocytic ehrlichiosis, after the recent reorganization of the families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales. Tick-borne fever (TBF), which is caused by the prototype of A. phagocytophilum, was first described in 1932 in Scotland. A similar disease caused by a related granulocytic agent was first described in horses in the USA in 1969; this was followed by the description of two distinct granulocy...
Pradel J, Chalvet Monfray K, Molia S, Vachiéry N, Rousteau A, Imbert D, Martinez D, Sabatier P, Lefrançois T.In Guadeloupe, West Nile virus (WNV) activity was first observed in equids in 2002, and a high seroprevalence was found in 2003. The objective of our study was to determine individual and environmental factors associated with the risk of WNV seropositivity during 2002-2003. Fieldwork was conducted to retrospectively determine the location of equids at the time of virus circulation and to collect information regarding environmental and individual variables. Sera were collected from 369 equids out of an estimated total population of less than 500. Thirty-four environmental and individual variabl...
Docherty DE, Samuel MD, Egstad KF, Griffin KM, Nolden CA, Karwal L, Ip HS.After the 2001 occurrence of West Nile virus (WNV) in Wisconsin (WI), we collected sera, during 2003-2006, from south-central WI mesopredators. We tested these sera to determine WNV antibody prevalence and geometric mean antibody titer (GMAT). Four-fold higher antibody prevalence and 2-fold higher GMAT in 2003-2004 indicated greater exposure of mesopredators to WNV during the apparent epizootic phase. The period 2005-2006 was likely the enzootic phase because WNV antibody prevalence fell to a level similar to other flaviviruses. Our results suggest that, in mesopredators, vector-borne transmis...
Russell CL, Heesom KJ, Arthur CJ, Helps CR, Mellor PS, Day MJ, Torsteinsdottir S, Björnsdóttir TS, Wilson AD.Culicoides spp. are vectors of several infectious diseases of veterinary importance and a major cause of allergy in horses and other livestock. Their saliva contains a number of proteins which enable blood feeding, enhance disease transmission and act as allergens. We report the construction of a novel cDNA library from Culicoides nubeculosus linked to the analysis of abundant salivary gland proteins by mass spectrometry. Fifty-four novel proteins sequences are described including those of the enzymes maltase, hyaluronidase and two serine proteases demonstrated to be present in Culicoides sali...
Valerio L, Marini F, Bongiorno G, Facchinelli L, Pombi M, Caputo B, Maroli M, Della Torre A.Knowledge of the frequency of contact between a mosquito species and its different hosts is essential to understand the role of each vector species in the transmission of diseases to humans and/or animals. However, no data are so far available on the feeding habits of Aedes albopictus in Italy or in other recently colonized temperate regions of Europe, due to difficulties in collecting blood-fed females of this diurnal and exophilic species. We analyzed Ae. albopictus host-feeding patterns in two urban and two rural sites within the area of Rome (Italy). Ae. albopictus was collected using stic...
Bartsch S, Bauer B, Wiemann A, Clausen PH, Steuber S.Host feeding patterns of engorged sibling species of the Culicoides obsoletus and Culicoides pulicaris groups captured during three nights on two selected farms maintaining either cattle, sheep, horses, and pigs (Seedorf, Brandenburg) or cattle, sheep, moufflons, and red and fallow deer (Paulinenaue, Brandenburg) were determined by polymerase chain reaction amplification using conserved primers and sets of species-specific primers derived from vertebrates mitochondrial cytochrome b. Out of a total of 177 blood meals analysed, 115 (65%) tested positive for a blood meal from vertebrates. 63.5% (...
Alonso-Padilla J, Loza-Rubio E, Escribano-Romero E, Córdoba L, Cuevas S, Mejía F, Calderón R, Milián F, Travassos Da Rosa A, Weaver SC....West Nile virus (WNV) was probably introduced in southern and northern Mexico from the USA in two independent events. Since then, WNV activity has been reported in several Mexican states bordering the USA and the Gulf of Mexico, but disease manifestations seen there in humans and equids are quite different to those observed in the USA. We have analysed WNV seroprevalence in asymptomatic, unvaccinated equids from two Mexican states where no data had been previously recorded. WNV IgG antibodies were detected in 31.6% (91/288) of equine sera from Chiapas and Puebla states (53.3% and 8.0%, respect...
Journal of medical entomologyDecember 9, 2008
Volume 45, Issue 6 1152-1155 doi: 10.1603/0022-2585(2008)45[1152:tobcbd]2.0.co;2
Schwint ON, Knowles DP, Ueti MW, Kappmeyer LS, Scoles GA.The tropical horse tick, Dermacentor nitens, is a natural vector of Babesia caballi in the Americas. B. caballi, one of the etiologic agents of equine piroplasmosis, occurs widely throughout the world, but the United States and a few other countries are considered to be free of infection. B. caballi is transovarially transmitted by the one-host tick D. nitens; we tested the hypothesis that B. caballi can persist in multiple generations of D. nitens in the absence of opportunity to reacquire infection from a susceptible equine host. Partially engorged female D. nitens were collected from a B. c...
Yang DK, Kim BH, Kweon CH, Nah JJ, Kim HJ, Lee KW, Yang YJ, Mun KW.Recent global warming trends may have a significant impact on vector-borne viral diseases, possibly affecting vector population dynamics and disease transmission. This study measured levels of hemagglutination-inhibition (HI) antibodies against Japanese encephalitis virus (JEV) and neutralizing antibodies against Akabane virus (AKAV) and Aino virus (AINV) for Thoroughbred horses in Korea. Blood samples were collected from 989 racehorses in several provinces, between October 2005 and March 2007. Sera were tested using either an HI assay or a virus neutralization test. Approximately half (49.7%;...
Vianna MC, Horta MC, Sangioni LA, Cortez A, Soares RM, Mafra CL, Galvão MA, Labruna MB, Gennari SM.The present study investigated the infection by spotted fever rickettsia in an endemic area for Brazilian spotted fever (BSF; caused by Rickettsia rickettsii) in Minas Gerais State, Brazil. Human, canine and equine sera samples, and Amblyomma cajennense adult ticks collected in a rural area of Itabira City, Minas Gerais State were tested for rickettsial infection. Through Immunofluorescence Assay (IFA) we demonstrated the presence of antibodies anti-R. rickettsii in 8.2%, 81.3% and 100% of the human, canine and equine sera, respectively. None of the 356 tick specimens analyzed were positive fo...
Passamonti F, Veronesi F, Cappelli K, Capomaccio S, Coppola G, Marenzoni ML, Piergili FD, Verini SA, Coletti M.Anaplasma phagocytophilum, the causative agent of granulocytic ehrlichiosis, affects several species of wild and domesticated mammals, including horses. In this work we compared direct and indirect methods to evaluate A. phagocytophilum presence in Central Italy: 135 sera were screened by IFA for A. phagocytophilum and other haemopathogens (Theileria equi and Babesia caballi). Each horse was also tested for A. phagocytophilum 16S rRNA with a nested-PCR technique. In order to examine the risk of A. phagocytophilum transmission, 114 ticks were examined for the presence of A. phagocytophilum by P...
El-Hage CM, McCluskey MJ, Azuolas JK.Ross River Virus (RRV) was believed to be the cause of acute illness in four horses around the Bellarine peninsula in south-west Victoria, Australia. The horses presented with clinical signs including petechial haemorrhages, lymphadenopathy, distal limb swelling and reluctance to move. Fibrinogen was also elevated in three of the four horses. Whilst no virus was isolated, serological testing revealed elevated RRV IgM titres in all horses indicating acute infection. The outbreak occurred at a time when a known RRV vector, the mosquito Aedes camptorhynchus was recorded at very high levels in the...
Bakhshi H, Beck C, Lecollinet S, Monier M, Mousson L, Zakeri S, Raz A, Arzamani K, Nourani L, Dinparast-Djadid N, Failloux AB.Recent expansion of arboviruses such as West Nile (WNV), Usutu (USUV), and tick-borne encephalitis (TBEV) over their natural range of distribution needs strengthening their surveillance. As common viral vertebrate hosts, birds and horses deserve special attention with routine serological surveillance. Here, we estimated the seroprevalence of WNV, USUV and TBEV in 160 migrating/resident birds and 60 horses sampled in Mazandaran, Golestan, North Khorasan, Kordestan provinces and Golestan province of Iran respectively. ELISA results showed that of 220 collected samples, 32 samples (14.54%), inclu...
Burkett-Cadena ND, Day JF, Unnasch TR.Eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) is a mosquito-borne pathogen found in eastern North America that causes severe disease in humans and horses. The mosquito Culiseta melanura (Coquillett) (Diptera: Culicidae) is the primary enzootic vector of EEEV throughout eastern North America while several mosquito species belonging to diverse genera serve as bridge vectors. The ecology of EEEV differs between northern and southern foci, with respect to phenology of outbreaks, important vertebrate hosts, and bridge vector species. Active transmission is limited t...
Williams DL, Issel CJ, Steelman CD, Adams WV, Benton CV.Biological and mechanical transmission trials with Psorophora columbiae (Dyar and Knab) and Aedes sollicitans (Walker) and ponies acutely infected with equine infectious anemia virus (EIAV) were negative. The EIAV antigen was detected by radioimmunoassay in Ae sollicitans immediately after the mosquitoes had fed on an acutely ill pony, but not 14 days after feeding. Psorophora columbiae mosquitoes had detectable EIAV antigen as determined by radioimmunoassay 24 hours after they fed on an acutely ill pony; this antigen was not detected again until 6 days after feeding and was still detected 14 ...
Vander Kelen PT, Downs JA, Stark LM, Loraamm RW, Anderson JH, Unnasch TR.Eastern Equine Encephalitis virus (EEEV) is an alphavirus with high pathogenicity in both humans and horses. Florida continues to have the highest occurrence of human cases in the USA, with four fatalities recorded in 2010. Unlike other states, Florida supports year-round EEEV transmission. This research uses GIS to examine spatial patterns of documented horse cases during 2005-2010 in order to understand the relationships between habitat and transmission intensity of EEEV in Florida. Methods: Cumulative incidence rates of EEE in horses were calculated for each county. Two cluster analyses wer...
Barnard BJ.The entry of Culicoides species into stables was examined by comparing the numbers of midges caught with identical light-traps under different conditions. The comparison was made between collections made inside an empty stable, a regularly cleaned stable and a dirty stable and those made outside the stables in a sleeping space open on two sides. The work was first done in the presence of cattle and sheep in adjoining paddocks and then repeated in their absence. A positive correlation was found between the numbers of C. imicola females caught out of doors and inside a clean stable. Removal of t...
Marchi PR, Rawlings P, Burroughs JN, Wellby M, Mertens PP, Mellor PS, Wade-Evans AM.Purified African horse sickness virus (AHSV) was fed, as part of a blood meal, to adult females from a susceptible colony of Culicoides variipennis, established in the insectories at the Institute for Animal Health, Pirbright Laboratory, UK. The meal consisted of heparinized blood obtained from ovine, bovine, equine (horse and donkey) or canine sources spiked with AHSV serotype 9 (AHSV9). The infectivity levels observed for C. variipennis varied significantly, according to the source of the blood sample. Comparison of the protein profiles obtained from AHSV9 incubated with the individual serum...
Ribeiro MF, da Silveira JA, Bastos CV.Tick-borne diseases in horses are caused by the intraerythrocytic protozoan parasites Theileria equi and Babesia caballi. Although T. equi is highly endemic in Latin America, the New World vector of this important parasite is controversial. The aim of this study was to test the ability of nymph Amblyomma cajennense ticks acquire infection by T. equi following feeding on infected horses. Three experiments were performed: tick acquisition of T. equi from an experimentally infected horse, tick acquisition of T. equi from naturally infected foals and tick acquisition of T. equi from a chronically ...
Luethy D.The continued recognition and emergence of alphavirus and flavivirus diseases is a growing veterinary and public health concern. As the global environment continues to change, mosquito-borne diseases will continue to evolve and expand. Continued development of readily available vaccines for the prevention of these diseases in humans and animals is essential to controlling epizootics of these diseases. Further research into effective antiviral treatments is also sorely needed. This article describes equine encephalitis viruses with a focus on clinical and public health considerations.
Sinclair M, Bührmann G, Gummow B.African Horsesickness (AHS) is a controlled disease in South Africa. The country is divided into an infected area and a control area. An outbreak of AHS in the control area can result in a ban of exports for at least 2 years. A retrospective epidemiological study was carried out on data collected during the 2004 AHS outbreak in the surveillance zone of the AHS control area in the Western Cape Province. The objective of this study was to describe the 2004 outbreak and compare it with the 1999 AHS outbreak in the same area. As part of the investigation, a questionnaire survey was conducted in th...
Ceylan O, Benedicto B, Ceylan C, Tumwebaze M, Galon EM, Liu M, Xuan X, Sevinc F.Common vector-borne diseases of horses include equine piroplasmosis (EP) caused by Babesia caballi and Theileria equi, and equine granulocytic anaplasmosis (EGA) caused by Anaplasma phagocytophilum. Equine piroplasmosis leads to severe health issues in horses and restrictions on the movement of horses internationally. Anaplasma phagocytophilum causes an acute febrile illness in horses and is also of zoonotic importance. In the present study, blood samples were collected from 152 Turkish racehorses from three different provinces (İzmir, Gaziantep, and Konya) of Turkey to investigate the preval...
Sellers RF, Maarouf AR.Outbreaks of vesicular stomatitis, serotype New Jersey, during epidemics in the United States and northern Mexico, 1982-5, were examined by backward trajectories of winds to investigate spread and possible sources. The outbreaks selected for analysis did not involve introduction of disease by infected animals. The findings indicate that wind could have been responsible for carrying infection from northern Mexico to Arizona and New Mexico and thence to Colorado and Utah and on to Wyoming, Idaho and Montana. The results of these analyses are consistent with the findings from T1 RNAse fingerprint...
Gale P, Kelly L, Snary EL.The emergence of bluetongue virus and Schmallenberg virus in Great Britain (GB) during the last decade has highlighted the need for understanding the relative importance of the various pathways of the entry of livestock arboviruses so as to help focus surveillance and mitigation. This study summarizes what is known for the main routes of entry and assesses the strength of the current evidence for and against. Entry through infected arthropod vectors is considered at the level of each life cycle stage for tick-, biting midge- and mosquito-borne viruses, and while there is evidence that this cou...
Stobierski MG, Signs K, Dinh E, Cooley TM, Melotti J, Schalow M, Patterson JS, Bolin SR, Walker ED.Eastern equine encephalomyelitis (EEE) is a mosquito-borne viral disease that is an emerging public health concern in the state of Michigan. Although Michigan has one of the highest incidence rates of EEE in the United States, much of the information known about cases in humans, equines, and other animals residing in Michigan is unpublished. This article summarizes such information and explores spatial trends in the historic distribution of EEE in Michigan. Outbreaks in Michigan have occurred over an 80-yr interval, involving only horses in 1942-1943 and 1973-1976, and then episodically from 1...
Fares W, Gdoura M, Dhrif H, Touzi H, Hogga N, Hannachi N, Mhalla S, Kacem S, Karray H, Bougatef S, Ben-Alaya N, Triki H.West Nile Virus (WNV) is an arbovirus transmitted by mosquito bite involving birds as reservoirs, humans and equines as accidental hosts. Eight distinct lineages (WNV-1 to WNV-8) have been identified: WNV-1 and WNV-2 infect humans and animals, and WNV-3 to WNV-8 have been identified only in vectors. WNV has been implicated in neuroinvasives infections, especially meningitis and encephalitis. Tunisia experienced three epidemics in 1997, 2003 and 2012. Serological studies on humans, equines and birds as well as the detection of the virus in the vector favour a fairly frequent circulation in the ...
Miranda J, Mattar S.Anaplasma and Ehrlichia species are important tick-borne pathogens that cause disease in cattle, dogs, horses and humans; with little information available about these agents in Colombia. The aim of this study was to provide molecular evidence for the presence of Anaplasma sp. and Ehrlichia sp. species in ticks collected from horses, dogs and cattle in Cordoba, Colombia. In this study, 1.105 ticks were removed from 226 zebu cattle (Bos indicus), 87 dogs (Canis lupus familiaris) and 19 horses (Equus caballus), from different localities of Cordoba. Ticks were identified taxonomically and PCR ass...
Cloonan MJ, O'Neill BJ, Vale TG, Carter IW, Williams JE.The sera of 468 blood donors and 63 domestic animals, collected from the south coast of New South Wales, were tested for the presence of antibodies to Ross River virus. Antibodies were detected in 7% of human sera, 25% of cow sera and 65% of horse sera. Using the blood donors as 'human sentinels', seroconversions were demonstrated in two donors from the Nowra-Kiama region and from a patient in the same area; none of the three had been outside of the study area during the period of seroconversion or at the time of infection. Of the 15 seropositive horses, 6 (40%) had lived continuously since bi...
Abbas I, Ahmed F, Muqaddas H, Alberti A, Varcasia A, Sedda L.Climate change can cause spatio-temporal shifts in the epidemiology of various vector borne pathogens, especially in vulnerable areas such as the Mediterranean Basin (MB). Among these pathogens, the West Nile virus (WNV) became endemic in the region. This systematic review and meta-analysis study summarizes WNV epidemiology, molecular characteristics, and surveillance in various MB countries, relying on data and scientific articles on WNV published during 2010-2023. The number of published articles varied across the three MB subregions: Southern Europe (n = 153), North Africa (n = 33), and...
Artsob H, Wright R, Shipp L, Spence L, Th'ng C.A study was undertaken in 1975 to determine California encephalitis virus activity in southern Ontario. Three thousand and sixty-one mosquitoes, primarily Aedes species, were divided into 104 pools and inoculated into suckling mice. Isolates of snowshoe hare virus were obtained from one pool each of Aedes fitchii and A. triseriatus mosquitoes collected in the Guelph area. Serological testing of horse sera revealed extensive virus activity in southern Ontario and indicated that horses may serve as excellent monitors for California encephalitis virus.
Schmidtmann ET, Robl MG, Carroll JF.The capability of field-collected American dog ticks, Dermacentor variabilis, to infect horses with Ehrlichia risticii, causative agent of Potomac horse fever (PHF), was examined by allowing adult ticks collected from horse farms with a history of PHF to feed on susceptible horses. More than 500 male and female ticks attached and fed on 3 test horses; however, no clinical or serologic evidence of PHF was observed in treated or control horses. All horses were challenge exposed with E risticii-infective blood by inoculation at 60 to 65 days after ticks fed, and all developed clinical PHF with su...
House JA.AHS is a noncontagious vector-borne disease of Equidae caused by Orbiviruses. Species susceptibility in decreasing order is horses, mules, donkeys, and zebras. The main vectors of AHS are culicoides. The disease is endemic in sub-Saharan Africa, but epizootics have occurred outside of this area on several occasions. The most recent outbreaks outside of the endemic area were in Spain, Morocco, and Portugal between 1987 and 1990. AHS causes mortality up to 95% and is classically divided into four clinical forms: the pulmonary, cardiac, mixed, and horse fever forms. Pathologic changes are subcuta...
Gerhardt R.The accidental introduction of West Nile Virus into New York City from the Old World in 1999 resulted in an epidemic in humans, horses, and birds that swept to the west coast in just 3 years. The virus is transmitted by infective mosquitoes among susceptible native birds, which serve as amplifying hosts. Clinical disease occurs in humans and horses, but not enough virus is produced in their blood to infect other mosquitoes; therefore, humans and horses are considered dead-end hosts. Humans can best protect themselves by remaining indoors during periods of high mosquito activity and/or by using...
Durand JP, Simon F, Tolou H.West Nile virus (WNV) is a common arbovirosis, transmitted by mosquitoes mainly Culex. WNV is commonly responsible for equine epizootics and epidemics in humans in sub-Saharan Africa. It has been occasionally described in Southern Europe and in some Mediterranean countries. Since 1994, WNV clinical aspects seem to change with an increase of central neurological involvement and a higher mortality, especially among people older than 50 years. In 1999, WNV reached New York, being responsible for severe clinical manifestations. It spread all over North America in less than four years Four (only fo...
Spissu N, Panichi G, Montisci A, Fiore F.West Nile Virus (WNV) is an enveloped, positive-sense RNA virus belonging to the genus Flavivirus, antigenically related to the Japanese encephalitis complex in the family Flaviviridae. The principal vectors are mosquitoes, in particular Culex spp, and virus amplification seems to occur in susceptible birds that are the principal vertebrate reservoir hosts, whereas humans, horses and other vertebrates are considered incidental or dead-end hosts. The first Italian equine outbreak was reported in late summer of 1998 in Tuscany, in the area surrounding the Fucecchio marshes, where 14 clinical cas...
Costa SCL, de Souza Freitas J, Carvalho FS, Pereira MJS, Cordeiro MD, da Fonseca AH, Gomes Jusi MM, Machado RZ, Munhoz AD.Currently, various zoonotic diseases are classified as emerging or reemerging. Because equids have a direct relationship with various vectors, they are possibly more frequently exposed to zoonotic agents than are humans. The undeniable importance of diseases such as human granulocytic anaplasmosis, spotted fever, and leishmaniasis for both public and animal health, as well as the possibility of equids acting as sources, reservoirs, or even sentinels for these pathogens, justifies the detection of their frequency and factors associated with infection in equids from northeastern Brazil. Methods:...
Paslaru AI, Torgerson PR, Veronesi E.Biting midges (Diptera: Ceratopogonidae) are arthropods of veterinary importance since they can transmit pathogens and cause severe allergic dermatitis in horses. Very little is known about the species at higher altitudes and their seasonal dynamics. In this work, adult Culicoides were collected with Onderstepoort UV-light suction traps (OVI) from June to September 2016 at two areas situated at around 1600 m asl (pre-alpine area I, 2 farms) and 2030 m asl (pre-alpine area II, 1 farm) in the Canton of Grisons (south-east Switzerland). Overall, 17 049 Culicoides were collected, including 8...
