Overview and features of larval developmental sites of biting midges species associated with livestock in Israel with implications to their control.

The larval developmental sites of Culicoides species were assessed from 1155 samples collected during the years 1969-2003. Culicoides circumscriptus was most prolific in mud with medium organic matter with proportional representation of 55.8%. Culicoides imicola breeds mainly in damp mixture of rotten, decomposed animal dung with or without some mud, with proportional representation of 97.2%. Culicoides obsoletus was found mostly in rotten banana stumps, with proportional representation of almost 100%. Culicoides puncticollis was found in mud with a medium amount of organic matter with proportional representation of 35.6%. Culicoides distinctipennis showed 22.2% proportional representation for mud poor in organic matter. Culicoides schultzei gr. was most prolifically in mud rich in organic matter with proportional representation of 6.2%. Culicoides cataneii was most prolifically in mud with a medium amount of organic matter with proportional representation of 1.8%. Maximum duration time to emergence from the larval developmental sites ranged from seven weeks in C. obsoletus to fourteen weeks in C. circumscriptus and nine weeks in C. imicola. All the studied species breed throughout the year. Significant innate differences in the proportions of the sexes were found in the emergence of six species.

Retrospective epidemiological investigation of an outbreak of bovine ephemeral fever in 1991 affecting dairy cattle herds on the Mediterranean coastal plain.

From August to October 1991 bovine ephemeral fever (BEF) occurred sporadically in two localities in Israel. The morbidity and mortality rates reached 2.6% and 0.1%, respectively. Only 12/50 dairy cattle herds were clinically infected with BEF in the dairy community. The total morbidity rate reached 0.8%. The lowest morbidity rate was recorded in young heifers (5.5%) and the highest in adult cows (75%). Only heifers over the age of three months were clinically affected. The spread of the disease apparently followed the local prevailing night winds, which blow from east to west, i.e., from the land toward the sea. The morbidity period lasted 61 days. The low incidence and morbidity rates were possibly due to the low virulence of the virus strain involved in the 1991 epidemic. Retrospective analysis indicates that vectors - apparently mosquitoes - infected with BEF virus could have been overwintering.

Seasonal allergic dermatitis in sheep associated with Ctenocephalides and Culicoides bites.

The clinical, epidemiological and histopathological findings of two pruritic dermatites in sheep in Israel are described. The first type of dermatitis affected mainly young animals with lesions predominantly on the legs. It occurred from March to November, with a peak in June. The second type affected animals of all ages and was mainly on the ventrum. It was sporadic but occurred throughout the year with a peak in October. The morbidity rate of this syndrome reached 4.3% in one flock. The histopathology of both conditions was consistent with an allergic dermatitis. Fleas and midges were collected and identified as Ctenocephalides felis felis and various species of Culicoides. The population density, seasonal activity, geographical distribution and feeding behaviour preferences of the insects and the incidence of the two types of dermatitis suggest that fleas and midges were the causal agents. Flea and midge bite pruritic dermatoses should be considered in the differential diagnosis of sarcoptic and psoroptic mange.

Predicting the risk of bluetongue through time: climate models of temporal patterns of outbreaks in Israel.

Determining the temporal relationship between climate and epidemics of Culicoides-borne viral disease may allow control and surveillance measures to be implemented earlier and more efficiently. In Israel, outbreaks of bluetongue (BT) have occurred almost annually since at least 1950, with severe episodes occurring periodically. In this paper, the authors model a twenty-year time-series of BT outbreaks in relation to climate. Satellite-derived correlates of low temperatures and high moisture levels increased the number of outbreaks per year. This is the first study to find a temporal relationship between the risk of Culicoides-borne disease and satellite-derived climate variables. Climatic conditions in the year preceding a BT episode, between October and December, coincident with the seasonal peak of vector abundance and outbreak numbers, appeared to be more importantthan spring or early summer conditions in the same year as the episode. Since Israel is an arid country, higher-than-average moisture levels during this period may increase the availability of breeding sites and refuges for adult Culicoides imicola vectors, while cooler-than-average temperatures will increase fecundity, offspring size and survival through adulthood in winter, which, in turn, increases the size of the initial vector population the following year. The proportion of variance in the annual BT outbreak time-series resulting from climate factors was relatively low, at around 20%. This was possibly due to temporal variation in other factors, such as viral incursions from surrounding countries and levels of herd immunity. Alternatively, since most BT virus (BTV) circulation in this region occurs silently, in resistant breeds of local sheep, the level of transmission is poorly correlated with outbreak notification so that strong relationships between BTV circulation and climate, if they exist, are obscured.

What factors determine when epidemics occur in the Mediterranean? Prediction of disease risk through time by climate-driven models of the temporal distribution of outbreaks in Israel.

Determination of the temporal relationships between climate and epidemics of Culicoides-borne viral disease may lead to control measures and surveillance being implemented earlier and more efficiently. Although Israel has reported few cases of bluetongue (BT) during the recent Mediterranean epidemic, outbreaks have occurred almost annually since the disease was first confirmed there (1950) with severe episodes occurring periodically. The south Mediterranean location and intensive farming of BT-susceptible European sheep breeds make the area ideal for investigation of the effect or role of climatic factors versus other potential host or virus factors in governing the timing of severe BT episodes. The authors present regression analyses of 20-year time-series of BT outbreaks versus four remotely sensed climatic variables. Low temperatures and high moisture levels (relative to average levels) in the preceding autumn coincident with the seasonal peak of vector abundance and outbreaks had a positive effect on the number of outbreaks the following year. The positive effects of high moisture levels are postulated to increase breeding site availability and refugia for adult C. imicola vectors (from desiccation) in autumn whilst low temperatures may increase fecundity, offspring size and survival through adulthood in winter by increasing initial vector population size the following year. The proportion of variance in the annual BT outbreak time series accounted for by climate factors was relatively low (approximately 20%), probably because most BT virus (BTV) circulation occurs silently, due to the circulation of non-virulent BTV strains, combined with the prevalence of relatively resistant local sheep breeds. Thus, the level of BTV transmission is poorly correlated with the rate of outbreak notification.

Susceptibility and repellency of Culicoides imicola and Culex pipiens to lambda-cyhalothrin.

The basic efficacy of lambda-cyhalothrin was tested in the laboratory against newly colonised adult Culex pipiens and field-collected Culicoides imicola. C. imicola was found to be more susceptible (LD(50)=0.0098%) than Cx. pipiens (LD=0.0233%); the efficacy against both species was definitely higher than that of cyhalothrin. Lambda-cyhalothrin showed slight repellency for C. imicola during the first hour post application.

Detection of Israel turkey meningo-encephalitis virus from mosquito (Diptera: Culicidae) and Culicoides (Diptera: Ceratopogonidae) species and its survival in Culex pipiens and Phlebotomus papatasi (Diptera: Phlebotomidae).

Israel turkey meningo-encephalitis (ITME) virus was detected in pools of Ochlerotatus caspius Pallas and Culicoides imicola Kieffer trapped at a turkey run at Nir David during an outbreak in August 1995. Experimental membrane feeding on a blood ITME suspension showed that Culex pipiens L. became harbored virus for at least 14 d. When Phlebotomus papatasi Scopoli were fed on an infected turkey, they became infected and harbored the virus for at least 7 d. Because Phlebotomines are trapped frequently at turkey runs in Israel, they should be suspected as potential vectors of ITME.

Phylogenetic status and matrilineal structure of the biting midge, Culicoides imicola, in Portugal, Rhodes and Israel.

The biting midge Culicoides imicola Kieffer (Diptera: Ceratopogonidae) is the most important Old World vector of African horse sickness (AHS) and bluetongue (BT). Recent increases of BT incidence in the Mediterranean basin are attributed to its increased abundance and distribution. The phylogenetic status and genetic structure of C. imicola in this region are unknown, despite the importance of these aspects for BT epidemiology in the North American BT vector. In this study, analyses of partial mitochondrial cytochrome oxidase subunit I gene (COI) sequences were used to infer phylogenetic relationships among 50 C. imicola from Portugal, Rhodes, Israel, and South Africa and four other species of the Imicola Complex from southern Africa, and to estimate levels of matrilineal subdivision in C. imicola between Portugal and Israel. Eleven haplotypes were detected in C. imicola, and these formed one well-supported clade in maximum likelihood and Bayesian trees implying that the C. imicola samples comprise one phylogenetic species. Molecular variance was distributed mainly between Portugal and Israel, with no haplotypes shared between these countries, suggesting that female-mediated gene flow at this scale has been either limited or non-existent. Our results provide phylogenetic evidence that C. imicola in the study areas are potentially competent AHS and BT vectors. The geographical structure of the C. imicola COI haplotypes was concordant with that of BT virus serotypes in recent BT outbreaks in the Mediterranean basin, suggesting that population subdivision in its vector can impose spatial constraints on BT virus transmission.

Reducing waste contamination from animal-processing plants by anaerobic thermophilic fermentation and by flesh fly digestion.

There is currently no market in Israel for the large amounts of waste from fish- and poultry-processing plants. Therefore, this waste is incinerated, as part of the measures to prevent the spread of pathogens. Anaerobic methanogenic thermophilic fermentation (AMTF) of wastes from the cattle-slaughtering industry was examined previously, as an effective system to treat pathogenic bacteria, and in this article, we discuss a combined method of digestion by thermophilic anaerobic bacteria and by flesh flies, as a means of waste treatment. The AMTF process was applied to the wastes on a laboratory scale, and digestion by rearing of flesh fly (Phaenicia sericata) and housefly (Musca domestica) larvae on the untreated raw material was done on a small scale and showed remarkable weight conversion to larvae. The yield from degradation of poultry waste by flesh fly was 22.47% (SD = 3.89) and that from fish waste degradation was 35.34% (SD = 12.42), which is significantly higher than that from rearing houseflies on a regular rearing medium. Bacterial contents before and after thermophilic anaerobic digestion, as well as the changes in the chemical composition of the components during the rearing of larvae, were also examined.

Epidemiological investigations of outbreaks of bovine ephemeral fever in Israel.

In two epidemics of bovine ephemeral fever (BEF) in Israel, one in 1990 and one in 1999, the virus was probably carried by vectors transported by air currents across the Rift Valley and through the Red Sea trough. The disease broke out under optimal ecological conditions among vulnerable cattle populations and spread rapidly; it developed in the spring and summer and ended soon after the daily average ambient temperature fell below 16 degrees C in late autumn. The proportion of herds affected reached 78.4 and 97.7 per cent in 1990 and 1999, respectively. The highest rates of incidence, morbidity and mortality were recorded in dairy cattle herds in the Jordan Valley, the initial focus of the outbreaks, with a morbidity of 20 and 38.6 per cent in 1990 and 1999, respectively, and mortality among the affected animals of 2 and 8.6 per cent in 1990 and 1999, respectively. In 1991, the disease recurred sporadically in the central and southern regions of Israel in only three herds, but in 2000 the disease returned on an epidemic scale, and 85 per cent of herds were affected, with morbidity and mortality rates of 4-3 and 0-3 per cent, respectively. In the 1999 epidemic, the morbidity rate decreased from 38-6 per cent on average in the Jordan Valley to 12.8 per cent in the inner valleys and 5.3 per cent on the Mediterranean coastal plain, but the mortality rate increased from 8-6 per cent in the Jordan Valley to 14-3 per cent in the inner valleys, and to 28 per cent on the Mediterranean coastal plain, where the outbreak declined. An average of 2-7 per cent of the animals experienced a second attack of the disease two to six weeks later. The epidemic in 2000 was milder and shorter than that in 1999. All the cattle affected in both outbreaks were more than three months old. The vector(s) is not known for certain but the available evidence indicates that mosquitoes, and not Culicoides species, are the natural vectors of BEF virus in Israel.

Dermatitis in humans associated with the mites Pyemotes tritici, Dermanyssus gallinae, Ornithonyssus bacoti and Androlaelaps casalis in Israel.

Multiple erythematous papules accompanied by severe pruritus were observed in humans bitten by the mites (Acari) Pyemotes tritici (Newport) (Pyemotidae), Dermanyssus gallinae (De Geer) (Dermanyssidae), Ornithonyssus bacoti Hirst (Macronyssidae) and Androlaelaps casalis (Berlese) (Laelapidae). Eight case histories are presented and the impact of these species on human health is discussed.

Study of apparent hypersensitivity to Culicoides species in sheep in Israel.

Between 1983 and 1997, a low incidence of seasonal allergic dermatitis was diagnosed in sheep in Israel aged eight months to eight years, in 10 flocks of a variety of breeds, but not the local Awassi breed. The 40 affected animals reacted with scratching, biting and vigorous stamping of the feet from April to November each year. The principal skin lesions were hyperkeratosis, spongiosis and infiltrations of eosinophils and mononuclear cells, typical of an allergic dermatitis which was probably a hypersensitivity reaction to biting insects. The epidemiological findings in relation to the area of Israel affected, the breeds of sheep and the distribution of the lesions suggested that the sheep's hypersensitivity was due to the bites of several species of Culicoides.

Feeding and survival of Culicoides sonorensis on cattle treated with permethrin or pirimiphos-methyl.

The persistence of permethrin (5% a.i.) and pirimiphos-methyl (27% a.i.), applied to the dorsum of calves in the field against Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae), was estimated using a hair-blood-feeding bioassay in the laboratory. Hair clippings were taken before treatment and 3, 7, 14, 21, 28, 42 and 56 days after treatment from the dorsum, side and belly of treated and control calves. Laboratory-reared insects were allowed to feed through thin hair layers and a parafilm membrane on sheep blood warmed using a water-jacketed feeder. Some intoxication after exposure to hair was noted up to 28 days after treatment with permethrin and up to 14 days after treatment with pirimiphos-methyl. Hair from the dorsum caused more intoxication for a longer period than hair from other body regions. Permethrin and pirimiphos-methyl applied to the back did not significantly reduce overall engorgement (body regions pooled) after treatment. Permethrin residues on hair remained far higher on the back than other body regions and were related to insect intoxication and reduction in engorgement in the laboratory. Residues on belly hair never exceeded 12p.p.m. and did not result in significantly reduced feeding at any time. Engorged insects that exhibited sublethal intoxication from feeding through permethrin-treated hair did recover and matured numbers of eggs comparable to controls. Field trials using treated and control calves and enclosure nets showed that dorsal applications of 5% permethrin were not effective in reducing engorgement, despite some intoxication. Vacuum samples from a calf showed that C. sonorensis fed primarily on the belly. A 0.2% permethrin application on the belly (250 ml) did result in > 80% reduction of C. sonorensis in the enclosure nets at 3 and 7 days after treatment, but activity had subsided by 10 days after treatment. The utility of insecticidal treatments for suppression of this vector is discussed.

Response of Culicoides sonorensis (Diptera: Ceratopogonidae) to 1-octen-3-ol and three plant-derived repellent formulations in the field.

The potential attractant 1-octen-3-ol and 3 potential repellents were assayed for activity for Culicoides sonorensis, the primary vector of bluetongue virus in North America. Collections using octenol were low, but numbers in suction traps were greater in the high-octenol treatment (11.5 mg/h) than in the low-octenol treatment (1.2 mg/h) or unbaited control for both sexes. Collections using high octenol, CO2 (approximately 1,000 ml/min), or both showed octenol alone to be significantly less attractive than either of the CO2 treatments and that octenol did not act synergistically with this level of CO2. A plant-derived (Meliaceae) extract with 4.5% of active ingredient (AI) (Ag1000), heptanone solvent, Lice free (2% AI from plant extracts in water), Mosi-guard with 50% Eucalyptus maculata var. citriodora Hook extract, and N,N-diethyl-m-toluamide (deet) were applied to polyester-cotton coarse mesh nets and deployed in conjunction with suction light traps plus CO2. Collections in the trap with deet were 66% lower (P < 0.05) than the heptanone and 56% (P > 0.05) less than the untreated (negative) control. Relative to deet, collections in the traps with the lice repellent, Ag1000, and Mosi-guard were reduced by 15, 34, and 39%, respectively (P > 0.05). The method has promise for field screening of potential repellents before on-animal testing.

The role of houseflies (Musca domestica) in harbouring Corynebacterium pseudotuberculosis in dairy herds in Israel.

A study was conducted to assess the role of houseflies, Musca domestica L. in harbouring Corynebacterium pseudotuberculosis in dairy farms in Israel. The bacterium was isolated in June 1993 from 40 wild houseflies which had fed on a lesion on a cow, and from 28 laboratory flies fed on contaminated milk from a cow infected with mastitis. The bacterium was recovered from the body surface of 10 flies (of a total of 160) 10 min after being dipped entirely in a bacterial broth. The bacterium was recovered from the body surface of 10 flies (of a total of 40) 5 min after being fed on contaminated milk. When 110 flies were fed on contaminated sugar cubes, the bacterium was recovered externally from 70 flies 5 min later, and from an additional 20 flies 10 min after feeding. Of 110 flies, 80 excreted bacteria in saliva from 5 min to 3 h after feeding on contaminated milk. Bacteria were isolated from the intestine of 40 of 60 flies between 1 h and 4 h after feeding on contaminated milk. Bacteria were found in the faeces of 30 of 60 flies, between 1 h and 4 h after feeding on contaminated milk. In the light of these findings, and given the fact that this species of fly has a predilection to feed on milk residues of cow teats, the authors concluded that the housefly plays an important role in harbouring and disseminating C. pseudotuberculosis in dairy herds in Israel. In contrast, stable flies (Stomoxys calcitrans L.) are not important in the habouring and dissemination of the bacteria, since bacteria were not recovered 5, 10, 15, 30 min, 2 h or 24 h after membrane feeding on a mixture of bacterial broth and blood.

Arthropod parasites of Nubian ibexes (Capra ibex nubiana) and gazelles (Gazella gazella) in Israel.

In a 20-year survey the following ectoparasites were collected from Nubian ibexes: larvae of an unidentified Oestrus sp. collected from the nasal cavities, sinuses and horns, hippoboscid flies (Lipoptena chalcomelaena) specific to the Nubian ibex, blood sucking lice (Linognathus africanus) and unidentified biting lice (Damalinia sp.). Ibexes were severely infested with the cattle tick, Boophilus annulatus; a few Hyalomma anatolicum excavatum ticks were also collected. In five ibexes kept in two zoos, showing otitis, Psoroptes cuniculi, was identified, and from skin scrpaings of nine animals with severe dermatitis in three other zoos, Sarcoptes scabiei was isolated. Infestation of Nubian ibexes with sucking and biting lice as well as H. anatolicum excavatum is reported for the first time. The ectoparasites collected from gazelles were: hippoboscid flies (Lipoptena capreoli), calliphorid flies (Lucilia sericata and Calliphora sp.), sucking lice (Linognathus africanus and Solenopotes capillatus) and unidentified biting lice (Damalinia sp.), fleas (Ctenocephalides felis felis), and ticks, B. annulatus, Rhipicepahlus bursa, Rhipicephalus turanicus, H. anatolicum excavatum and H. marginatum rufipes. In skin scrapings of four gazelles with local dermatitis in the fetlocks Chorioptes bovis was identified. Neoschoengastia sp. was found in craters between the claws in three gazelles.

Review of the palearctic desert biting midges Culicoides langeroni group, with a description of a new species (Diptera: Ceratopogonidae).

The biting midges of the Culicoides langeroni group, which consists of 4 species: C. langeroni Kieffer, C. judaeae Macfie, C. pseudolangeroni Kremer, Chaker & Delecolle, and 1 new species, C. molotovae, are reviewed.

Mosquito repellent attracts Culicoides imicola (Diptera: Ceratopogonidae).

A plant-derived mosquito repellent, based on the oil of Eucalyptus maculata var. citriodora Hook, was evaluated against the biting midge Culicoides imicola Kieffer. Suction black light-traps covered with repellent-impregnated polyester mesh and deployed near horses attracted large numbers of C. imicola, which were seen near the treated net within a few minutes of the start of the experiment. Initial collections in the traps were approximately 3 times as large as those in control traps with untreated mesh. Numbers collected in treated traps were similar to untreated control traps after 4 h. Traps with mesh treated with DEET or another plant-derived (Meliaceae) proprietary product, AG1000, acted as repellents relative to the control. The differential activity of repellents against blood-feeding Diptera is discussed.

Duration of repellency of various synthetic and plant-derived preparations for Culicoides imicola, the vector of African horse sickness virus.

Objectives of the study were threefold: to find a safer and longer lasting repellent of the biting midge Culicoides imicola than di-ethyl toluamide (DEET), to examine whether the current recommendations in Israel for application of repellents during an outbreak of C. imicola-borne pathogens are justified; and to examine whether plant-derived preparations that have no known detrimental side effects are potential replacements of synthetic repellents. Of the seven repellents tested, those inferior to DEET were: oregano and Herbipet which showed a slight non-significant repellency for 2 h and 1 h respectively and Stomoxin which showed significant (P < 0.05) repellency for only 1 h. As the active ingredient of Stomoxin is permethrin, this suggests that recommendations to spray animals with this insecticide to prevent the spread of C. imicola-borne pathogens are not useful. Tri-Tec14 showed significant (P < 0.05) repellency with respect to controls for 2 h only, but performed similarly to, or slightly better than DEET. The repellents clearly superior to DEET were: the plant-derived material Ag1000 that repelled significantly (P < 0.05) with respect to controls for up to 4 h following a similar pattern to but somewhat more strongly than DEET, and pyrethroid-T which exerted significant (P < 0.05) repellency for 9 h. Pyrethroid-T proved to be the best repellent tested and if sprayed nightly it might provide protection from C. imicola-borne pathogens.