Climate influences assemblages of abomasal nematodes of sheep on steppe pastures in the east of Algeria.

It is a common view that assemblages of parasitic nematodes are influenced by climatic conditions; however, there are only a few articles available regarding those that infect farm animals. We investigated the relationship between climate variables and infection with abomasal trichostrongyles in 335 1-year-old rams grazed on steppe pastures in Eastern Algeria. Abomasa were collected from 12 local slaughterhouses located in four climatic areas (from humid to arid) and the worms extracted, identified and counted. The abundance was low and the fauna composed primarily of Teladorsagia circumcincta, Marshallagia marshalli and Trichostrongylus sp. The high percentage of M. marshalli is typical of steppe areas. Ostertagia ostertagi and Haemonchus contortus were present in low numbers. Rainfall was the most important climatic variable related to the main species. This relationship was not linear for M. marshalli but an optimal rainfall was detected (350-400 mm/year). The more complex climatic indicators used in the study did not demonstrate a more significant correlation than rainfall. The predictive value of rainfall on the abundance or proportion of species in the assemblage was modest but highly significant. The seasonality of assemblages was different between the two main sub-climates (sub-humid and semi-arid).

Report on Gasterophilus spp. (Diptera, Gasterophilidae) of Horses in Algeria: Prevalence, Intensity, and Monthly Variations.

The composition, prevalence, and seasonal dynamic of Gasterophilus species were studied at the slaughterhouse of Constantine region (East Algeria) in 128 horses over an 18 months period. Our survey revealed that 124 (96.9%) horses were infected with a mean intensity of 161 larvae of Gasterophilus spp. Four species of Gasterophilus were identified; Gasterophilus intestinalis and G. nasalis were by far the predominant species with 95.3% and 77.3% respectively, followed by G. haemorrhoidalis (14.0%) and G. pecorum (10.1%). The age, sex, and breed of horses did not affect the distribution of the infection. Second-stage larvae (L2) of G. intestinalis were absent between April and July and present in higher numbers between December and February. In addition, third-stage larvae (L3) were few in number, mainly from September to November, a consequence of their fecal elimination and suggesting that the effective period of adult activity of G. intestinalis is autumn. Therefore, the population dynamics of G. nasalis shows that its activity is two months longer and occurs earlier than that of G. intestinalis. The incidence of G. pecorum infection was linked to the rainiest months.

La composition, la prévalence et la dynamique saisonnière des espèces de Gasterophilus (ou gastérophiles) ont été étudiées à l'abattoir de la région de Constantine (est de l'Algérie) chez 128 chevaux sur une période de 18 mois. L'enquête a révélé que 124 (96,9 %) chevaux étaient infectés avec une intensité moyenne de 161 larves de Gasterophilus spp. Quatre espèces de Gasterophilus ont été identifiées. Gasterophilus intestinalis et G. nasalis étaient de loin les espèces prédominantes avec respectivement 95,3 % et 77,3 %, suivis de G. haemorrhoidalis (14,0 %) et de G. pecorum (10,1 %). L'âge, le sexe et la race des chevaux n'ont pas affecté la répartition de l'infection. Les L2 de G. intestinalis étaient absentes entre avril et juillet et présentes en nombre maximum entre décembre et février. De plus, les L3 étaient peu nombreuses principalement de septembre à novembre, une conséquence de leur élimination fécale, ce qui suggère que la période effective d'activité adulte de G. intestinalis est l'automne. La dynamique de population de G. nasalis a montré que son activité était plus longue de deux mois et se produisait plus tôt que celle de G. intestinalis. L'incidence de l'infection à G. pecorum était liée aux mois les plus pluvieux.

Towards finding effective indicators (diarrhoea and anaemia scores and weight gains) for the implementation of targeted selective treatment against the gastro-intestinal nematodes in lambs in a steppic environment.

The effective application of targeted selective treatment (TST) against gastro-intestinal nematodes depends on the accurate identification of those animals in need of anthelmintic treatment. Finding cost and labour effective measures to identify such animals is paramount. This study tested the efficacy of three indicators on lambs in a farm in Eastern Algeria: anaemia score (FAMACHA(©)), diarrhoea score (DISCO) and weight gain. These were contrasted against traditional parasitological infection measures (nematode eggs per gram of faeces: EPG). Thirty lambs were used in the study; every second month they were sampled (FAMACHA(©), faecal samples for EPG and DISCO, weight gains) and two of the original 30 lambs were necropsied for adult worm counts. The main gastro-intestinal nematodes were Teladorsagia circumcincta, Marshallagia marshalli, Nematodirus helvetianus, Trichostrongylus vitrinus, and Haemonchus contortus. DISCO proved to be the most effective indicator correctly identifying 80% of the sheep in need of treatment. This was followed by FAMACHA(©) with a 50% accuracy level and finally weight gains, which were not found to be a useful indicator at all.

The steppe species of gastrointestinal nematodes of small ruminants, with a focus on Marshallagia: climate as a key determinant.

We intended to relate the geographic distribution of ruminant gastrointestinal nematodes in relation to steppe climate (and vegetation). Data are either from literature or from newly acquired/available results. Simple or more sophisticated meteorological indices were used to characterize the climate. Regression analyses were used to correlate climatic factors and presence of endoparasites from steppe areas. The distribution of one (Marshallagia) out of five endoparasite genera was concentrated mostly in steppic areas whereas other species were found also in other areas. In wild hosts the distribution of Marshallagia was much larger from Sptizberg to New World (northern territories in Canada or extreme south of America). In domestic small ruminants the presence of Marshallagia was identified more frequently and constantly in the area of original domestication and its early diffusion (from Northern Africa to Kashmir, Caucasia). The distribution of this parasite was correlated to low rainfalls which were not the case for all other endoparasites. After host switch (reindeer or south America camelids), it has expanded in other climatic areas, either colder or dryer.

Repeated treatment faecal egg counts to identify gastrointestinal nematode resistance in a context of low-level infection of sheep on farms in eastern Algeria.

The efficacy of benzimidazoles and ivermectin was tested in 14 pilot farms in eastern Algeria. Resistance was detected in strongyle nematodes against benzimidazoles (five farms) and ivermectin (one farm). The main genera in the region were resistant: Teladorsagia, Trichostrongylus, Marshallagia and Nematodirus. The evaluations based on FECRT (faecal egg count reduction tests) were not always consistent due to the low-level of infection, and we developed a simplified, repeated treatment strategy to investigate resistance. The results obtained with repeated treatment faecal egg counts match globally those obtained with conventional faecal egg count reduction tests. This simplified, repeated treatment method should be investigated further since it is quicker, and this could make it possible to test larger farm samplings.

Analysis of helminth genetic data: comparative examples with Haemonchus contortus isozymes using exact tests or resampling procedures.

Population genetic data on helminths are scarce and it is important to fine tune analyses of these data, the interpretation of which is based on between-(Fst) and within-(Fis) population variability. Several computer programs are available and confidence intervals of each index are based on different procedures. These programs (Genetix, Diploid, Genepop) were compared with a classical program (Biosys-1) using a large set of Haemonchus contortus isozyme data. The results were identical for all softwares for large differences when natural populations were studied (Fst > 0.25 and Fis > 0.15 or <-0.15). When small Fst were investigated in laboratory-reared populations, the significance of differences was often related to the software used. As a rule of thumb, it is suggested that at least two out of three software packages (based on different calculation procedures) should give similar results before differences are validated.

[Epidemiology of tardive dyskinesias in the Maghreb]. / Epidémiologie des dyskinésies tardives au Maghreb.

The most prescribed type of psychotropic medication in maghrebian psychiatry is neuroleptics. It is therefore legitimate to study the epidemiology of the most frequent side-effect of long-term treatment with neuroleptics: Tardive Dyskinesia (TD). At the moment, a collaborative study is under way on epidemiology of TD within the framework of the Maghrebian Association of Biological Psychiatry; several studies have also been conducted on this topic in the University Psychiatric Centre Ibn Rochd, Casablanca, Morocco in 1984, 1986 and 1987. For the maghrebian study, only preliminary results from Tunis will be presented. These studies have been interested in two epidemiological aspects: prevalence of TD in hospitalized and out-patients treated with neuroleptics; prevalence of TD-like movements among never treated schizophrenics. The assessment tool used for all the studies was the Abnormal Involuntary Movement Scale (AIMS). Main results of these studies are: 1) General prevalence of TD and risk factors in neuroleptized patients: In Tunis, Douki and Benamor in their on-going study, found a general prevalence of 20.50% (N = 200 in patients). A multi-factor analysis showed that risk factors are (in decreasing order): female gender, age above 60, associated depression, total duration of neuroleptic treatment above 20 years, a frequently discontinued treatment, shock therapies in antecedents or associated, a diagnosis of non schizophrenic psychosis, haloperidol intake below 25 mg and fluphenazine depot above 100 mg daily. In Casablanca, in 1984, Chorfi found a general prevalence of 10% (N = 50 out-patients). In 1986, Bentounsi found a 14.50% prevalence in Casablanca (N = 400 out-patients) and 63.97% in the oldest psychiatric hospital in Morocco in Berreshid (N = 605 in-patients).(ABSTRACT TRUNCATED AT 250 WORDS)