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Endy, T. P., & Nisalak, A. (2002). Japanese encephalitis virus: ecology and epidemiology. Curr Top Microbiol Immunol, 267, 11–48.
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Sanchez-Vizcaino, J. M. (2004). Control and eradication of African horse sickness with vaccine. Dev Biol (Basel), 119, 255–258.
Abstract: African horse sickness (AHS) is an infectious but no-contagious viral disease of equidae with high mortality in horses. The disease is caused by an arthropod-borne double-stranded RNA virus within the genus Orbivirus of the family Reoviridae transmitted by at least two species of Culicoides. Nine different serotypes have been described. The nine serotypes of AHS have been described in eastern and southern Africa. Only AHS serotypes 9 and 4 have been found in West Africa from where they occasionally spread into countries surrounding the Mediterranean. Examples of outbreaks that have occurred outside Africa are: in the Middle East (1959-1963), in Spain (serotype 9, 1966, serotype 4, 1987-1990), and in Portugal (serotype 4, 1989) and Morocco (serotype 4, 1989-1991). Laboratory diagnosis of AHS is essential. Although the clinical signs and lesions are characteristic, they can be confused with those of other diseases. Several techniques have been adapted for the detection of RNA segments, antibodies and antigen. Two types of vaccines have been described for AHS virus. Attenuated live vaccines (monovalent and polyvalent) for use in horses, mules and donkeys, are currently available, as well as a monovalent, serotype 4, inactivated vaccine, produced commercially but no longer available. New vaccines, including a subunit vaccine, have been evaluated experimentally. In this paper a review of the last AHS outbreaks in Spain, occurring during 1987-1990, and affecting the central and south part of the country, is presented. The role that vaccination played for the control and eradication of the disease, as well as other aspects such as climatological conditions, number of vectors and horse management, are also presented and evaluated.
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Valero, N. (2003). West Nile virus: a new challenge? Invest Clin, 44(3), 175–177.
Abstract: West Nile Virus (WNV), a member of the family Flaviviridae, was first isolated in 1937. Since the original isolation of the WNV outbreaks have occurred with increase in frequency of cases in humans and horses, apparent increase in severe human disease and high avian death rates. In 1999, 2000 and 2002 outbreaks of the WNV encephalitis were reported in horses, birds and humans from New York and Canada. Ornithophilic mosquitoes are the principal vectors of the WNV and birds of several species chiefly migrants appear to be the major introductory or amplifying host. The pattern of outbreaks in the old and new world suggests that viremic migratory birds may also contribute to movement of the virus. If so, Central America, Caribbean Islands and countries of South America including Venezuela, are in potential risk for suffering a severe outbreak for WNV, since several species of birds have populations that pass trough New York and cross the western north Atlantic or Caribbean Sea. It is important the knowledge of the ecology of WNV as well of the efficacy of control efforts in order to minimize the public health impact in these countries, where all population is susceptible to this infection.
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Ulloa, A., Gonzalez-Ceron, L., & Rodriguez, M. H. (2006). Host selection and gonotrophic cycle length of Anopheles punctimacula in southern Mexico. J Am Mosq Control Assoc, 22(4), 648–653.
Abstract: The host preference, survival rates, and length of the gonotrophic cycle of Anopheles punctimacula was investigated in southern Mexico. Mosquitoes were collected in 15-day separate experiments during the rainy and dry seasons. Daily changes in the parous-nulliparous ratio were recorded and the gonotrophic cycle length was estimated by a time series analysis. Anopheles punctimacula was most abundant during the dry season and preferred animals to humans. The daily survival rate in mosquitoes collected in animal traps was 0.96 (parity rate = 0.86; gonotrophic cycle = 4 days). The length of gonotrophic cycle of 4 days was estimated on the base of a high correlation coefficient value appearing every 4 days. The minimum time estimated for developing mature eggs after blood feeding was 72 h. The proportion of mosquitoes living enough to transmit Plasmodium vivax malaria during the dry season was 0.35.
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Loyola, E. G., Rodriguez, M. H., Gonzalez, L., Arredondo, J. I., Bown, D. N., & Vaca, M. A. (1990). Effect of indoor residual spraying of DDT and bendiocarb on the feeding patterns of Anopheles pseudopunctipennis in Mexico. J Am Mosq Control Assoc, 6(4), 635–640.
Abstract: Intense and persistent use of DDT for malaria control has increased resistance and induced exophilic behavior of Anopheles pseudopunctipennis. An evaluation of bendiocarb and DDT to control this species in Sinaloa, Mexico, showed that, in spite of DDT-resistance, both insecticides produced similar effects. Feeding patterns were analyzed to explain these results. Resting mosquitoes were collected over the dry and wet seasons. Anophelines were tested in an ELISA to determine the source of the meals. The human blood index (HBI) ranged from 3.3 to 6.8% in DDT- and from 12.7 to 26.9% in bendiocarb-sprayed houses. Irritability and repellency in DDT-sprayed houses could explain the reduced HBI. In contrast, bendiocarb produced higher mortality. These effects could have affected different components of the vectorial capacity and similarly reduced malaria.
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Crans, W. J., McNelly, J., Schulze, T. L., & Main, A. (1986). Isolation of eastern equine encephalitis virus from Aedes sollicitans during an epizootic in southern New Jersey. J Am Mosq Control Assoc, 2(1), 68–72.
Abstract: Eastern equine encephalitis virus (EEE) was isolated from the salt marsh mosquito, Aedes sollicitans, collected from coastal areas of New Jersey on 3 occasions during the late summer and fall of 1982. The isolations were made at a time when local Culiseta melanura were either undergoing a population increase or exhibiting high levels of EEE virus. Although no human cases were reported during the epizootic period, the data lend support to the hypothesis that Ae. sollicitans is capable of functioning as an epidemic vector in the coastal areas of New Jersey where human cases of EEE have been most common.
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Mitchell, C. J., Darsie, R. F. J., Monath, T. P., Sabattini, M. S., & Daffner, J. (1985). The use of an animal-baited net trap for collecting mosquitoes during western equine encephalitis investigations in Argentina. J Am Mosq Control Assoc, 1(1), 43–47.
Abstract: A large net trap was used to sample mosquito populations attracted to horses at three sites each in Santa Fe and Rio Negro Provinces, Argentina, during the austral summer of 1984. These provinces, as well as others in Argentina, were affected by a severe epizootic of western equine encephalitis (WEE) during 1982-83. Totals of 2,752 and 6,929 mosquitoes were collected in Santa Fe and Rio Negro Provinces during five and three trap nights, respectively. Culex mosquitoes of the subgenus Culex were predominant (45.8% of total) in the Santa Fe collections, although Aedes albifasciatus also was prevalent (21.7%). The latter species was predominant (95.7% of total) in the Rio Negro collections. The mosquito fauna was less complex (minimum of 6 species) in Rio Negro Province as compared to Santa Fe Province (minimum of 18 species). The advantages of the net trap indicate that this trap can become a useful tool in arbovirus ecology studies in other areas.
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Lemasson, J. J., Fontenille, D., Lochouarn, L., Dia, I., Simard, F., Ba, K., et al. (1997). Comparison of behavior and vector efficiency of Anopheles gambiae and An. arabiensis (Diptera:Culicidae) in Barkedji, a Sahelian area of Senegal. J Med Entomol, 34(4), 396–403.
Abstract: The ecology, population dynamics, and malaria vector efficiency of Anopheles gambiae and An. arabiensis were studied for 2 yr in a Sahelian village of Senegal. Anophelines were captured at human bait and resting indoors by pyrethrum spray. Mosquitoes belonging to the An. gambiae complex were identified by polymerase chain reaction. Of 26,973 females, An. arabiensis represented 79% of the mosquitoes captured and remained in the study area longer than An. gambiae after the rains terminated. There were no differences in nocturnal biting cycles or endophagous rates between An. gambiae and An. arabiensis. Based on an enzyme-linked immunosorbent assay test of bloodmeals, the anthropophilic rate of these 2 vectors were both approximately 60%, when comparisons were made during the same period. Overall, 18% of the resting females had patent mixed bloodmeals, mainly human-bovine. The parity rates of An. gambiae and An. arabiensis varied temporally. Despite similar behavior, the Plasmodium falciparum circumsporozoite protein (CSP) rates were different between An. gambiae (4.1%) and An. arabiensis (1.3%). P. malariae and P. ovale only represented 4% of the total Plasmodium identified in mosquitoes. Transmission was seasonal, occurring mainly during 4 mo. The CSP entomological inoculation rates were 128 bites per human per year for the 1st yr and 100 for the 2nd yr. Because of the combination of a high human biting rate and a low CSP rate, An. arabiensis accounted for 63% of transmission. Possible origin of differences in CSP rate between An. gambiae and An. arabiensis is discussed in relation to the parity rate, blood feeding frequency, and the hypothesis of genetic factors.
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Washino, R. K., & Tempelis, C. H. (1967). Host-feeding patterns of Anopheles freeborni in the Sacramento Valley, California. J Med Entomol, 4(3), 311–314.
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Sinclair, M., Buhrmann, G., & Gummow, B. (2006). An epidemiological investigation of the African horsesickness outbreak in the Western Cape Province of South Africa in 2004 and its relevance to the current equine export protocol. J S Afr Vet Assoc, 77(4), 191–196.
Abstract: 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 the 30 km radius surrounding the index case. Spatial, temporal and population patterns for the outbreak are described. The investigation found that the outbreak occurred before any significant rainfall and that the main AHS vector (Culicoides imicola) was present in abundance during the outbreak. Furthermore, 63% of cases occurred at temperatures < or = 15 degrees C, the Eerste River Valley was a high risk area, only 17% of owners used vector protection as a control measure and 70% of horses in the outbreak area were protected by means of vaccination at the start of the outbreak. The study revealed that the current AHS control measures do not function optimally because of the high percentage of vaccinated horses in the surveillance zone, which results in insufficient sentinel animals and the consequent failure of the early warning system. Alternative options for control that allow continued export are discussed in the paper.
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