Conjunctival papillomas in norther Canadian natives.

Cases of conjunctival papilloma evaluated at a hospital that acts as a referral centre for native people (Indian and Inuit) from northern Alberta and the Northwest Territories were compared with those from other hospitals in the same region whose referral base is primarily non-native. When the data were standardized for population unitsof 100,000 the tumours appeared to be occurring with a greater frequency among lnuit of the Western Arctic. These findings are supported statistically, although it is possible that bias may have been introduced by the small number of cases and other related factors.     

Desertification in the Sahel: a reinterpretation

The impact of human management, in particular livestock grazing, on the vegetation cover of the Sahel is still debated. In a range of studies, satellite images have been used to analyze the development of the Sahelian vegetation cover over time. These studies did not reveal any significant degradation of the Sahel in the last two decades. In this paper, we examine the ecological assumptions underlying the use of satellite imagery to analyze degradation of the Sahel. Specifically, we analyze the variability of the rain‐use efficiency (RUE), which is often used as an indicator for the state of the vegetation cover. We detect a fundamental flaw in the way RUE has been handled in most remote sensing studies; they ignored the relation between annual rainfall variation and RUE. Because of the upward trend in annual rainfall that occurred during the 1980s and 1990s, this leads to a bias in the interpretation of the satellite images. In this paper, we show the importance of the variability in RUE for the analysis of remote sensing imagery of semiarid rangelands. Our analysis also shows that it is likely that there has been anthropogenic degradation of the Sahelian vegetation cover in the last two decades. This has important consequences for the debate on the impacts of grazing on semiarid rangelands. Furthermore, the occurrence of anthropogenic degradation is relevant to explain the magnitude of 20th century Sahelian droughts. The analyses also indicate that the population of the Sahel may be more vulnerable for droughts than currently assumed.     

Gastrointestinal myiasis by larvae of Sarcophaga sp. and Oestrus sp. in Egypt: report of cases, and endoscopical and morphological studies

Four cases of gastric or intestinal myiasis are reported. The cases contain 2 males (1 child 10 years old, and 1 adult 40 years old) and 2 females (1 girl 18 years old, and 1 adult 50 years old) from Minia Governorate, Southern Egypt. Three of them, including cases no. 1, 3, and 4, were gastric myiasis, and complained of offensive hematemesis of bright red blood. Minute moving worms, larvae of the fly, were found in the vomitus. On the other hand, case no. 2 had intestinal myiasis, and complained of abdominal distention, nausea, vomiting, and diarrhea. The stool of case 2 was mixed with blood, and minute moving worms were observed in the stool. Endoscopy was performed to explore any pathological changes in the stomach of the patients. The larvae were collected and studied macroscopically, microscopically, and us-ing a scanning electron microscope (SEM) to identify their species. Three different types of larvae were identified. The larvae isolated from case 1 were diagnosed as the second stage larvae of Sarcophaga species, and the larvae isolated from case 2 were the third stage larvae of Sarcophaga species. On the other hand, the larvae isolated from cases 3 and 4 were diagnosed as the third stage larvae of Oestrus species.     

Oral myiasis in an elderly patient

doi: 10.1111/j.1741‐2358.2010.00432.x Oral myiasis in an elderly patient Background: Myiasis is the invasion of living tissue of humans and other mammals by eggs or maggots of flies of the order of Diptera. It occurs mainly in the Tropics and is associated with inadequate public and personal hygiene. Oral myiases in an older man appears to be rare. Objective: To relate a case of oral myiases in a debilitated older man treated by mechanical removal of the maggots, identifying the adult insect that caused the infestation. Methods: The diagnosis of oral myiasis was established by the clinical examination and it was detected that the infestation involved only soft tissue and the sinus cavity. The patient was submitted to two mechanical removal of the visible maggots. Results: Total of 110 maggots was removed from the oral cavity of the patient and adult insects was identified as belonging to the Calliphoridae Family, Cochliomyia hominivorax species. The patient died two days after the second procedure by severe systemic complications. Conclusions: The mechanic removal and the identification of the maggots must be adopted as soon as possible to prevent further tissue damage and bacterial infection in cases of oral myiasis. Special attention should be given to the debilitated old patients that are particularly susceptible to oral myiasis infestation.     

Dry season reproductive depression of Anopheles gambiae in the Sahel

The African malaria mosquito, Anopheles gambiae, is widespread south of the Sahara including in dry savannahs and semi-arid environments where no surface water exists for several months a year. Adults of the M form of An. gambiae persist through the long dry season, when no surface waters are available, by increasing their maximal survival from 4 weeks to 7 months. Dry season diapause (aestivation) presumably underlies this extended survival. Diapause in adult insects is intrinsically linked to depressed reproduction. To determine if reproduction of the Sahelian M form is depressed during the dry season, we assessed seasonal changes in oviposition, egg batch size, and egg development, as well as insemination rate and blood feeding in wild caught mosquitoes. Results from xeric Sahelian and riparian populations were compared. Oviposition response in the Sahelian M form dropped from 70% during the wet season to 20% during the dry season while the mean egg batch size among those that laid eggs fell from 173 to 101. Correspondingly, the fraction of females that exhibited gonotrophic dissociation increased over the dry season from 5% to 45%, while a similar fraction of the population retained developed eggs despite having access to water. This depression in reproduction the Sahelian M form was not caused by a reduced insemination rate. Seasonal variation in these reproductive parameters of the riparian M form population was less extreme and the duration of reproductive depression was shorter. Blood feeding responses did not change with the season in either population. Depressed reproduction during the dry season in the Sahelian M form of An. gambiae provides additional evidence for aestivation and illuminates the physiological processes involved. The differences between the Sahelian and riparian population suggest an adaptive cline in aestivation phenotypes between populations only 130 km apart.     

Desertification in the Sahel: a reinterpretation of a reinterpretation

In semiarid regions the ratio of annual net primary production to precipitation, rain-use efficiency (RUE), has been used as an index of desertification. In a recent publication ( Hein & de Ridder, 2006 ) it was proposed that an incorrect understanding of the relationship between RUE and rainfall has led to a misinterpretation of the satellite record of desertification in the African Sahel. Here, we examine this suggestion and show that, contrary to Hein and de Ridder's statement, satellite studies of Sahelian RUE have reported increases, decreases, and constant values since 1981. Furthermore, we find that data do not support their proposal that RUE increases with rainfall, even in nondegraded areas. Hence we reject their corollary, that constant RUE is prima facie evidence of desertification. The fundamental difficulty with the use of RUE for detection of desertification remains, that is the difficulty of estimation of the RUE for nondegraded land at a regional scale.     

Between-season Survival of the Grasshopper Pathogen Metarhizium flavoviride in the Sahel

A study is presented showing that the entomopathogenic fungus, Metarhizium flavoviride, can persist in fragments of infected grasshopper cadaver and survive the Sahelian dry season. A significant positive relationship was identified between the probability of mortality at the beginning of one season and the density of infected cadavers present in the habitat at the end of the previous season. Furthermore, survival analysis revealed a steady decline in the mean survival time of grasshoppers exposed to the infected habitats as the density of infected cadavers used to seed the habitat increased. The consequences of these findings are discussed in the context of the use of M. flavoviride for locust and grasshopper control.     

Organochlorine residues in the Tunisian market basket

This paper provides preliminary findings on organochlorine residues in Tunisian foodstuffs, i.e.: butter, milk, cheese, fish, canned tuna and sardines, beef, egg yolk, chicken and beef liver. The techniques used are HPLC, MS-GC, ECD-GC.     

Pulmonary Aspergillus niger intracavitary colonization. Report of 23 cases and a review of the literature

In this study we have compared clinical data obtained from 40 reported cases of pulmonary Aspergillus niger intracavitary colonization in the literature and those of our series 23 cases. Additionaly six of our cases have been summarized. Our findings revealed a similar occurrence of male sex, active tuberculosis, diabetes mellitus, systemic oxalosis, and lethal outcome in both groups. In conclusion, A. niger is not the most frequent causative agent of saprophytic aspergillosis neither is the most pathogenic species of Aspergillus. Despite that, when pulmonary A. niger intracavitary colonization is associated with diabetes the prognosis is generaly poor, probably due to acute oxalosis.     

A first case of myiasis in fish

Maggots of an unidentified species of Caliphora were discovered in freshwater fish, Astyanax mexicanus fasciatus, shipped from Hong Kong to Norway. This represents the first reported case of myiasis in fish.     

Oestrid myiasis in European mouflon from Spain

From February 1992 to March 1997, 245 European mouflon (Ovis orientalis musimon) from Sierras de Cazorla, Segura y Las Villas Natural Park (southern Spain) were surveyed for oestrid larvae in order to estimate prevalence and mean intensity of parasitism by Oestrus ovis. Over 46 percent of the animals surveyed were infected, with a mean intensity of 9.6 larvae/host parasitized. No significant differences in prevalence rates between host sexes were observed, but older mouflons were infected with more larvae than younger ones.