Comparing terpenes from plant essential oils as pesticides for the poultry red mite (Dermanyssus gallinae).

Resistance to conventional synthetic pesticides has been widely reported in ticks, parasitic mites and other pests of veterinary and medical significance. New and novel approaches to manage these pests are therefore needed to ensure efficient control programmes that can be implemented now and in the future. Recent research in this area has focused on the pesticidal potential of plant essential oils. These products are attractive as pesticide candidates on the grounds of low mammalian toxicity, short environmental persistence and complex chemistries (limiting the development of pest resistance against them). Although issues may exist concerning reliability in efficacy of essential oils, these may be overcome by identifying and developing bioactive oil components for use in pest management. In the current work, three such components (terpenes) found in essential oils (eugenol, geraniol and citral) were tested against the poultry red mite Dermanyssus gallinae. All provided 100% mortality in toxicity tests when undiluted. Even at 1% of this dose, eugenol was 20% effective against experimental pest populations, although the remaining terpenes were largely ineffective at this concentration.

Efficacy of 1% geraniol (Fulltec) as a tick repellent.

A field trial on the efficacy of 1% geraniol (Fulltec) spray against ticks has been carried out in two farms near Rabat (Morocco). Results clearly revealed that 1% geraniol has a preventive effect against Hyalomma ticks. Comparison of geraniol sprayed cows with control herd showed a reduction of mean number of ticks per animal of 98.4%, 97.3% and 91.3% at respectively day 7, 14 and 21 post-spraying. These data give evidence that the geraniol, natural product extracted from plants, could be an alternative to limit use of chemical acaricides, which efficacy is compromised by development of resistance.

Molecular genetic analysis of populations of Wohlfahrt's wound myiasis fly, Wohlfahrtia magnifica, in outbreak populations from Greece and Morocco.

Wohlfahrt's wound myiasis fly, Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae), is the most important cause of traumatic myiasis in the southern Palaearctic region. Larval stages are obligate parasites and the wounds caused by infestations are very similar to those caused by Old and New World screwworm flies. During the last decade, W. magnifica appears to have expanded its range to parts of northern and central Morocco, and to Crete, Greece. Specimens of W. magnifica were collected in Morocco and Crete either as larvae (preserved in 80% ethanol) or as adults (dry-pinned). Comparison specimens were collected in Spain, Hungary and mainland Greece. A DNA fragment containing the 3' 715 base pairs of the mitochondrial cytochrome b gene was amplified by polymerase chain reaction from each of 132 larvae or adults of W. magnifica and the amplicons were directly sequenced and analysed phylogeographically. Twelve cytochrome b haplotypes were detected. All haplotypes from Morocco belonged to a lineage that included specimens from the Iberian peninsula, and restricted mixing of central and northern populations in Morocco was demonstrated. Cytochrome b haplotyping combined with an analysis of larval size provided clear evidence of multiple infestations of hosts in all geographical areas, with one quarter of wounds containing larvae from two to at least four females. More than 80% of specimens from Crete contained a haplotype predominating in mainland Greece and Hungary. Our survey indicated that wohlfahrtiosis was more widespread in northern and central Morocco than previously recorded by government veterinarians. However, the prevalence of wohlfahrtiosis was low (< 1%). The high genetic diversity of Moroccan populations is consistent with longterm endemicity, rather than recent introduction. Crete showed a higher prevalence of wohlfahrtiosis (< or = 15%) and less genetic diversity of W. magnifica, which is consistent with a recent introduction. The western and eastern Mediterranean lineages may have been isolated in different Pleistocene ice-age refugia, from which there has been limited post-glacial dispersal.

Traumatic myiasis in dogs caused by Wohlfahrtia magnifica and its importance in the epidemiology of wohlfahrtiosis of livestock.

In the province of Al Hoceima, northern Morocco, and on two farms in Hungary, dogs were inspected for the presence of traumatic myiasis. Nine and four infested dogs were found in Morocco and Hungary, respectively. All the larvae and adults reared from them in the laboratory were identified as Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae). To our knowledge, these are the first cases of wohlfahrtiosis in dogs to be reported in these countries. All infested animals lived close to livestock, where wohlfahrtiosis was endemic. Infested body sites included limbs (six cases), external genitalia (two), ears (three), nose (one) and neck (one). Developing larvae caused severe welfare problems and tissue destruction in most cases. Although the number of cases reported here is small, wohlfahrtiosis in dogs may be very important from an epidemiological perspective because farm and stray dogs can act as both reservoirs and carriers of this parasitic fly species. Therefore, education of dog owners concerning the risk factors in endemic regions is recommended in order to reduce the prevalence of wohlfahrtiosis in dogs and thereby in livestock. Both owners and veterinarians should pay regular attention to any wounds and to the natural orifices of dogs, especially during the fly seasons.

[Wound myiasis due to Wohlfahrtia magnifica. First human case in Morocco]. / Myiase des plaies dues à Wohlfahrtia magnifica (Schiner, 1862). Premier cas humain au Maroc.

Wohlfahrtia magnifica is a frequent fly in countries with high breeding activity: Australia, South Africa or Arab country The parasitological infestation occurred essentially during the summer, favourable period to the biological evolution of the flies. In this work, we report one case of wound myiasis that complicates a cutaneous lesion caused by larvae of Wohlfahrtia magnifica. This observation constitutes the first human case in our country.

Population genetics and dynamics at short spatial scale in Bulinus truncatus, the intermediate host of Schistosoma haematobium, in Morocco.

The population biology of the schistosome-vector snail Bulinus truncatus was studied in an irrigation system near Marrakech, Morocco using both genetic and demographic approaches. The population genetic survey was conducted in 4 sites, 2 sites being sampled on 2 separate occasions. Individuals were genotyped at 6 microsatellite loci. No variability was found at 4 loci, and the 2 other loci had less than 4 alleles. The differentiation, both spatial and temporal, among populations was extremely weak. The demographic survey was conducted using 2 capture-mark-recapture analyses in 2 separate sites, the first in 1999 and the second in 2000. The second analysis permitted the estimation of parameters based on recent methodological developments (multisite models). Although these studies provided information on several traits, we report here on dispersal only. Both analyses showed that individual dispersal is of the order of a few hundreds of metres per reproductive life, that is the scale of the whole irrigation area. Both the genetic and demographic studies indicated that this area harbours a single--or no more than a few--populations of B. truncatus. This has implications for our understanding of the coevolutionary process between snails and flukes.

New challenges in schistosomiasis control in Morocco.

Cases of schistosomiasis were first detected in 1914. However, there is strong evidence that it was prevailing in the southern part of Morocco long before then. As reported from different African countries, over the last three decades, the development of irrigation has led to the spread of the disease to the north and centre of the country. Thereafter, a national programme of schistosomiasis control was launched by the Ministry of Health in 1983. The programme was based on case detection and treatment, snail control using chemicals, and health education. It has succeeded in reducing the prevalence and intensity of infection to a level low enough to allow an elimination programme to be launched in 1994. The aim is to reach a complete elimination of the disease by the year 2004 in all provinces affected. Though substantial progress was made since the programme started, there is a potential risk of outbreaks in many affected provinces. Therefore, an integrated approach including measures against the intermediate host is needed to reach the goal of elimination. The present paper sheds some light on the features of schistosomiasis in Morocco and presents an evaluation of environmental methods of control of Bulinus truncatus in Tessaout Amont and Akka oasis irrigation schemes. The role of community involvement in planning and implementing environmental measures against the snail intermediate host in modern and traditional irrigation schemes is also discussed.

Evaluation of environmental methods to control snails in an irrigation system in Central Morocco.

The Moroccan Ministry of Public Health has launched a programme to eliminate schistosomiasis. One of the components in this process is the control of Bulinus truncatus, the intermediate host snail of Schistosoma haematobium. We evaluated three environmentally safe measures to control B. truncatus in siphon boxes, the main breeding sites for these snails in the Tessaout Amont irrigation system. The first method involved covering the siphon boxes to exclude light and reduce algal growth, the second consisted of increasing the frequency of emptying and cleaning the siphon boxes, and the third method increased water velocity to hinder the establishment of the intermediate hosts. The results showed that covering had a pronounced effect on snail and egg mass density, was accepted by the local community and prevented water contact. Cleaning the siphons three times during the irrigation season led to a reduction in snail density although it was not statistically significant and recolonization was rapid. Increasing water velocity by reducing the dimensions of siphon boxes delayed recolonization, but such a control measure can be applied only in specific situations where it does not pose hydraulic problems. The three interventions were selectively effective against B. truncatus, whereas other snails such as Physa acuta and Lymnaea peregra were hardly affected. Covering, the most promising control measure, could be useful in the Moroccan schistosomiasis eradication programme. However, further investigations are needed to assess its impact on water quality.

Schistosoma haematobium in Morocco: moving from control to elimination.

In this article, Hammou Laamrani and colleagues summarize the Moroccan schistosomiasis control programme and discuss the challenges ahead for schistosomiasis elimination. In 1994, a programme was initiated by the Moroccan Ministry of Health to eliminate schistosomiasis from Morocco by the year 2004. In 1997, this objective had been achieved in three out of 20 affected provinces. This article discusses the background and strategies of this programme, as well as the achievements, the problems encountered and the challenges ahead, along with suggestions as to how to reach the goal of elimination of urinary schistosomiasis in Morocco, and possibly elsewhere in Africa.

Evaluation of three methods to control Bulinus truncatus, the intermediate host of Schistosoma haematobium in an irrigation scheme, Tessaout-Amont, Morocco.

In Morocco, the implementation of new irrigation schemes resulted in the introduction of schistosomiasis haematobium to new areas. Canal structures (especially syphon boxes) were found to be favourable habitats for Bulinus truncatus and they constitute important transmission sites. Three methods for snail control in these syphon boxes were assessed in the Tessaout-Amont irrigation scheme. Molluscicide (niclosamide) application resulted in a pronounced reduction in the snail population density, but snails started to recolonise the sites a few months later. Regular brushing of the inner sides of the syphon boxes and covering the syphon boxes, so as to exclude light, resulted in significant reductions in snail numbers. However, the latter methods were not as efficient as the molluscicide.

The study of human behavior and schistosomiasis transmission in an irrigated area in Morocco.

This paper presents a research strategy for studying water contact, water use and schistosomiasis transmission in an irrigated area of Morocco. This setting, with many scattered water contact sites, many activities carried out at these sites, and the small number of people involved, was not appropriate for a conventional water contact study based on the observation of water contact sites, such as had been carried out in the Nile delta. The Moroccan study utilizes three related concepts: the household, time geography, and the gendered use of space. It seeks to understand processes and interrelationships underlying the daily mobility pattern of individual households, and seen as part of a larger system of organization and structure in time and space. The preliminary results of the study indicated the complexity and dynamism of water use and water contact, which need to be considered in planning disease control strategies especially in changing settings, such as those associated with environmental interventions in the study area.

Effects of an anthelmintic treatment programme on sheep productivity in the Middle Atlas, Morocco.

This study evaluated the production advantages of the strategic anthelmintic treatment of both lambs and ewes in an area endemic for gastro-intestinal nematodes, lungworms and liver flukes. The liver fluke infections were generally chronic. The lambs were treated with albendazole (SmithKline Beecham), fenbendazole (Hoechst Roussel) or a vitamin supplement and their weight gains were followed over the next 7 months. The control group, which received a vitamin supplement only, gained 6.67 kg from July to January. The group that received fenbendazole, an anthelmintic with no activity against liver flukes, gained 10.42 kg over the study period. The third group which received albendazole, an anthelmintic with efficacy against liver flukes, gained 13.07 kg over the same period. Lamb deaths apparently due to liver flukes were 12, 4, and zero for the control, fenbendazole and albendazole groups, respectively. Similar advantages were observed in the ewes. Deaths were 16, 8, and zero in the control, fenbendazole and albendazole groups, respectively. The lambing rate in the control group was significantly lower than that in either of the 2 treated groups. The number of services per conception was significantly lower in the albendazole treated group than that in either of the other groups. These studies demonstrated the advantages of anthelmintic treatment in sheep in a helminth endemic area. While removing gastro-intestinal nematodes and lungworms improved production, the additional removal of liver flukes enhanced production gains as well as reducing deaths.

Seasonal patterns in the transmission of Schistosoma haematobium in Attaouia, Morocco.

In the Attaouia area, the density of Bulinus truncatus (Audouin, 1827), was monitored monthly for a period of one year in correlation with weather variations. Snails were active throughout the year and particularly abundant at the end of spring and summer. Two snail generations were found to overlap. The infection rate of B. truncatus reached a maximum of 3.5% in the summer when human water contact was frequent. A selective survey conducted in the village of Lamyayha showed that the prevalence of infection with S. haematobium among the local population was 21.2% who were passing from 10 to 80 eggs per 10 ml of urine.

Seasonal dynamics of Fasciola hepatica burdens in grazing Timahdit sheep in Morocco.

Seasonal transmission of Fasciola hepatica was observed in sentinel sheep and the dynamics of the snail intermediate host, Lymnaea truncatula, was followed over a 3-year study period in the Middle-Atlas mountains in Morocco. High fluke burdens were recorded in both lambs and ewes in the fall and winter, suggesting that transmission occurred in late spring. Fluke burdens ranged from one to 302 in ewes and from one to 345 in lambs. Infections with 200 or more flukes were always fatal. A unique feature of this study was the annual cyclical fluctuation of the fluke burdens. Burdens reached maximum levels during the winter and then declined to low numbers by late spring and summer. This suggested self-regulation which may be dependent on breed resistance or may be related to forage factors, including lack of forage (nutritional stress). Snail populations were cyclical and correlated with fluke transmission as observed in the sentinel sheep. The weather was observed to affect the snail populations which in turn limited fluke transmission.

[Seasonal variations of Fasciola hepatica infection in goats in the area of Haouz (Morocco)]. / Variations saisonnières de l'infestation par Fasciola hepatica chez la chèvre dans la région du Haouz (Maroc).

The prevalence and level of infection with Fasciola hepatica were assessed monthly over a 12-month period in goats slaughtered in the Haouz area, in correlation with the dynamics of Lymnaea truncatula populations. The infection rate was high in winter (23.8%) in January), and summer (17.1% in August), and relatively low in spring and at the beginning of autumn. The infected animals had a fluke burden range of 1-48; a mean of 13 was recorded in July. Lymnaeid snails were observed in their habitat throughout the year, but were more abundant during the hot months (July and August). Snails infected with F hepatica were found in February, June, July and August; their infection rate did not exceed 3%. These data enabled us to hypothesize that the main periods for transmission of fascioliasis were spring and fall; however, potential infections during other periods of the year were possible. The susceptibility of goats to infection with F hepatica appears to be similar to that reported in sheep.

[Physiopathology of ovine ostertagiasis. Effects of experimental infection by Ostertagia circumscripta on various parameters as indicators of abomasum function]. / Physiopathologie de l'ostertagiose ovine. Effets de l'infestation expérimentale par Ostertagia circumcincta sur quelques paramètres témoins de l'état de fonctionnement de l'abomasum.

The measurement of the pH and Na+, K+, Ca++ and Cl- concentrations of the stomach or the abomasal contents allow the functioning statement of these organs to be determined. In the present work, these parameters were measured, at 2 day intervals, in six lambs fitted with permanent abomasal cannulae and experimentally infected with 150 000 O. circumcincta infective larvae. Infection was followed by a significant (P less than 0.01) increase in pH and Na+ and Ca++ concentrations, and a significant (P less than 0.01) decrease in K+ and Cl- concentrations of the abomasal contents. The disorders start when the 4th stage larvae begin to emerge from the mucosae (from the 4th to the 12th day infection) and become more marked between the 16th and the 32nd day; this means when the egg output starts and becomes marked. The disturbances noted in the present work suggest: 1) a defective working of HCl production mechanism; 2) an intraluminal diffusion of the interstitial liquid; 3) a stimulation of pepsin production. These disorders would have consequences on the functioning of the other parts of the digestive tract.