Oestrus ovis myiasis in Libyan sheep and goats.

The heads of 1,489 sheep and 320 goats were examined for larvae of Oestrus ovis at 17 abattoirs in northern Libya in July to November 1988. The prevalence of O. ovis in sheep was 22.6% and in goats it was 18.4 per cent. Up to 14 and 11 larvae were collected from individual sheep and goats respectively. All larvae were recovered from the nasal passages and frontal sinuses, but only second and third instars were seen.

Lice of farm animals in Libya.

This first report on the lice of farm animals in Libya lists a total of fifteen species, as follows: Haematopinus quadripertusus and Linognathus vituli from cattle, Bovicola ovis, Linognathus pedalis, L. africanus and L. ovillus from sheep, L. stenopsis, L. africanus and Bovicola caprae from goats. Poultry harboured Lipeurus caponis, L. heterographus, Menacanthus stramineus, Menopon gallinae, Goniocotes gallinae, Goniodes gigas and G. dissimilis.

A survey of mites on farm animals in Libya.

In 1985-1988, 2287 farm animals (cattle, camels, sheep, goats, horses, donkeys, dogs and rabbits) suspected of carrying parasitic mites were examined at 58 farms throughout Libya. Mites were identified on 1303 of these animals. The commonest parasites on cattle were Psoroptes and Chorioptes, on camels and sheep were Sarcoptes and Psoroptes, and on goats were Sarcoptes and Demodex. Infested horses carrier Psoroptes or Chorioptes, and one donkey carried Sarcoptes. Otodectes was common on dogs, but Sarcoptes was rare and no Demodex were seen. Rabbits often had psoroptic ear mange or sarcoptic body mange. Dermanyssus gallinae and Ornithonyssus bursa were seen on chickens, but no mites were found on pigeons, ducks or turkeys.

A survey of ticks on farm animals in Libya.

Thirteen species of ixodid ticks and two species of argasid ticks were collected during a three-year survey of 58 farms in Libya. These included Boophilus annulatus, B. microplus, B. decoloratus, seven species of Hyalomma, Rhipicephalus sanguineus, Rh. evertsi, Rh. bursa, Argas persicus and Ornithodoros foleyi. This is the first recording of B. microplus, B. decoloratus and Rh. bursa in Libya. Of 20,391 animals examined by random sampling, 2020 (9.6%) had ticks; particularly common were Hy. dromedarii on camels, Hy. impeltatum on sheep and Hy. excavatum on cattle. The tick found most frequently overall was Hy. dromedarii.

Prevalence of human hydatid disease in northwestern Libya: a cross-sectional ultrasound study.

A total of 4103 people were screened in an ultrasound survey of the prevalence of hydatid disease (Echinococcus granulosus) in five areas of northwestern Libya; hydatid cysts were seen in 57 (1.4%), an overall prevalence of approximately 2.0% when adjusted for the likelihood of the occurrence of cysts in other sites in the body. All ultrasound-positive cases were confirmed by dot-blot ELISA. The prevalence of hydatid cysts increased with age, and differed between the sexes except in the five to 14 age group. All diagnosed cases, even those with large cysts, were asymptomatic. This study demonstrates the value of ultrasonography for screening field populations for hydatid disease. The technique was well received locally, facilitating the rapid collection of prevalence data from all ages and both sexes. Libyan people keep guard dogs, but there is little direct human:dog contact. Many people own a single dog, invariably kept outside and often chained up. Stray dogs are common, roaming the countryside to scavenge sheep carcases etc., and such dogs could be the main reservoir of E. granulosus in Libya. Because of the minimal direct human:dog contact, transmission of hydatid disease in Libya is probably indirect by ingestion of eggs from contaminated vegetables or drinking water.

Experimental infection of Libyan sheep with Echinococcus granulosus.

The growth rate of unilocular hydatid cysts over a two-year period was studied in Libyan sheep dosed orally with gravid segments of Echinococcus granulosus taken from stray town dogs. Seven of the eight sheep dosed with 20-100 gravid segments (say 4000-20,000 eggs) had developed only infertile hydatid cysts after 107-611 days. Sheep dosed with 1000 gravid segments (say 200,000 eggs) had developed only sterile cysts when examined 358 days after dosing. Fertile cysts were recovered from the lungs after 428 days, and after 584 days from the liver. Only sterile cysts were seen in the heart, spleen and kidneys.

The New World screw-worm fly in north Africa.

The course of the North African outbreak of New World screw-worm myiasis (Cochliomyia hominivorax) since its discovery in 1988 is described. Chemical and biological control measures are reviewed, including the current progress of the 'sterile male' (SIT) eradication programme.

Echinococcosis in Libya. III. Further studies on the prevalence of Echinococcus granulosus in dogs.

Of 92 dogs examined for Echinococcus granulosus at five sites in Libya from April 1985 to September 1988 33 (35.9%) were infected, the prevalences ranging from 60% (Zawiyah) and 52.0% (Tripoli) in the north-west, to 28.6% (Benghazi) and 28.5% (Darna) in the north-east. None of eight dogs at Al-Kufra, in the south-eastern desert, were infected. Twenty dogs each had two to 200 worms, nine had 201-1000 worms and four each had over 1000 worms (one dog in Tripoli had 17,120 worms). Most infections were seen in dogs aged three to four years; 45.4% of bitches and 35.4% of males were infected.

Echinococcosis in Libya. IV. Prevalence of hydatidosis (Echinococcus granulosus) in goats, cattle and camels.

During a survey of 14 Libyan abattoirs in 1985-1987 the carcasses of 4316 locally-bred goats, cattle and camels were inspected for cysts of Echinococcus granulosus. Of 2295 goats, 35 adults (1.5%) had cysts; no kids were infected. Thirty-one adult goats had infected livers, 28 had lung infections, and four each had cysts in their kidneys and spleens. Most (59.7%) of the infections were light, with medium infections in 31.3% and heavy infections in 8.9%; 85.7% of the cysts in the lungs and 38.7% of those in the livers were fertile; three of the four kidney infections and two of the four spleen infections were fertile. Of the 1023 cattle carcasses, mild infections with E. granulosus were seen in 55 (5.4%); all the cysts were sterile and confined to the liver. Of 998 camels, 358 (35.9%) had hydatid cysts. These involved the lungs in 96.9%, either as the sole site (74.3%) or jointly with the liver (22.6%). Lung cysts (57.6%) and liver cysts (41.2%) were fertile.

The screwworm fly in Libya: a threat to the livestock industry of the Old World.

The screwworm fly, Cochliomyia hominivorax (Coquerel), is the most serious insect pest of cattle in the New World. It has recently been recorded in Libya, where it appears to have become established. This article documents these recent finds, and provides background information on the recognition of the fly, its biology, distribution and importance.

Echinococcosis in Libya. II. Prevalence of hydatidosis (Echinococcus granulosus) in sheep.

The incidence and geographical distribution of hydatidosis was examined in sheep from ten localities in Libya. A total of 402 cases of hydatid disease (7.85%) were confirmed in a total of 5118 sheep examined; 12.74% of adult sheep were infected, but only 0.29% of lambs. The liver was the organ most commonly infected (97.26% of all infections), followed by the lungs (58.70%), kidneys (1.76%), spleen (0.74%) and heart, mesentery and muscles (0.24% each). The intensity of infection varied from one to more than ten fertile or sterile cysts. Infections were light in 43.73% of livers and 47.03% of lungs, medium in 33.24% of livers and 42.79% of lungs, heavy in 13.55% of livers and 7.62% of lungs, and very heavy in 9.96% of livers and 2.54% of lungs. A total of 73.13% of the infections were found to be fertile, 18.90% sterile and 7.96% both sterile and partly calcified. Lung hydatids tended to be more fertile than liver cysts.

The ecological basis of parasite control: ticks and flies.

Tick and fly control programmes have undergone radical review in recent years. Insecticidal control measures are now often seen as a means of reducing target populations to a level sufficiently low for final eradication by biological or ecological techniques, the sterile male method (SIRM) being particularly favoured. As a preliminary, the new range of insecticidal application techniques includes insecticidal tags, bands, blouses, implants and pheromone baits. The final eradication programme could then involve the use of sterile flies or sterile hybrid ticks, for example. Immunization of cattle against ticks, the use of tick-resistant crossbreeds of cattle, tick-repellent grasses and dung burying beetles are among the additional techniques now being actively investigated.