Spermiogenesis and spermatozoon ultrastructure of the cranial digenean Troglotrema acutum (Leuckart, 1842)

Ultrastructure of spermiogenesis and the main characters of the mature spermatozoon of Troglotrema acutum are described by means of transmission electron microscopy. Specimens were obtained from the nasolacrimal sinuses of an American mink (Mustela vison). Spermiogenesis in T. acutum follows the general pattern of digeneans. The zone of differentiation is a conical-shaped area bordered by cortical microtubules and delimited at its base by a ring of arched membranes. This area contains 2 centrioles associated with striated rootlets and an intercentriolar body between them. The centrioles develop 2 free flagella that grow ortogonally to the median cytoplasmic process. The posterior flagellar rotation and proximodistal fusion of the free flagella with the median cytoplasmic process originate the spermatozoon. The mature spermatozoon of T. acutum is characterized by the presence of 2 axonemes of different lengths presenting the 9+'1' trepaxonematan pattern, 2 bundles of parallel cortical microtubules, 2 mitochondria, a nucleus, and granules of glycogen. These ultrastructural characters are compared with other digenean species previously studied and the importance of different spermatological features is discussed.

[Cavicola myiasis caused by many Oestrus ovis (Linnaeus, 1761, Diptera: Oestridae) larvae in a sheep]

When the head of a sheep was split into two along its longitudinal axis during a pathological examination, a large number of Oestrus ovis larvae were found in the nasal cavities, middle nasal meatus and sinuses of the sheep. A total of 114 Oestrus ovis larvae were collected, including 87 (76.32%) first stage larvae, 25 (21.93%) second stage larvae and 2 (1.75%) third stage larvae from the regions given above.

Seasonal variations in the larval burden distribution of Oestrus ovis in sheep in the southwest of Spain

A chronobiological study of oestrosis was conducted for larval instars of Oestrus ovis from November 2000 to September 2002 with the examination of 477 adult sheep of the southwest region of Spain. Skulls from slaughtered sheep were examined and the different O. ovis larval stages (L1, L2, L3) were recovered from the nasal-sinus cavities. O. ovis larvae were detected in 339 sheep, reaching a prevalence of 71.1%. Only one farm was free of infested sheep indicating a prevalence of the 97.91% among studied flocks. The mean larval burden was 18.54 larvae per infested head during the coldest months in the southwest of Spain when the larval burden reached its highest levels, especially of the first larval stage (L1). However, the maximum percentage of L1 coincided with the minimum percentage of the second larval stage (L2). The third larval stage (L3) was observed in relatively low levels during the entered study period, but two peaks occurred in April-May and in September-October. During the 2 years of sampling, all the different larval stages were simultaneously recovered throughout the year, indicating the existence of a long favourable period for the evolution and development of the larval instars, which would start between February and March and finishing in November.

Paranasal sinus bony structures and sinus functioning during viral colds in subjects with and without a history of recurrent sinusitis

OBJECTIVES/HYPOTHESIS

The objective was to assess the impact of ostial obstruction and anatomical variations on paranasal sinus functioning during viral colds with computed tomography (CT) in subjects with and without a history of sinusitis.

STUDY DESIGN

Cross-sectional study.

METHODS

Twenty-three volunteers with a history of recurrent sinusitis and 25 subjects without such history who had an early (symptoms for 2-4 d) natural cold were examined by taking viral specimens and CT scans and recording symptoms. The pathological sinus changes in the CT scans were scored, and several paranasal bony anatomical variations recorded.

RESULTS

Viral origin of the cold was identified in 32 (67%) subjects, similarly in the two groups. Ostiomeatal obstruction and anatomical variations were equally frequent in the subjects with and without a sinusitis history (17 of 23 vs. 17 of 25 for ostial obstruction and 17 of 23 vs. 20 of 25 for at least one variation, respectively). However, in the case of ostiomeatal obstruction the combined CT score of ethmoidal and maxillary sinuses was significantly higher in the subjects with a sinusitis history than in those without (mean +/- SD, 3.0 +/- 0.9 vs. 2.3 +/- 1.2 [P =.05, t test]). In the sinusitis-prone subjects, several variations were associated significantly with various pathological sinus CT changes (septal deviation, horizontally situated processus uncinatus, large concha bullosa, and laterally concave concha media), whereas in the control subjects, only the presence of Haller cells was related to sphenoidal sinus disease.

CONCLUSION

Ostiomeatal complex obstruction and bony anatomical variations seem to have a greater impact on the functioning of paranasal sinuses during viral colds in sinusitis-prone subjects than in subjects without a sinusitis history. These differences may be associated with the increased risk of bacterial sinusitis.

Rileyella petauri gen. nov., sp. nov. (Pentastomida: Cephalobaenida) from the lungs and nasal sinus of Petaurus breviceps (Marsupialia: Petauridae) in Australia

A new cephalobaenid pentastome, Rileyella petauri gen: nov., sp. nov. from the lungs and nasal sinus of the petaurid marsupial, Petaurus breviceps, is described. It is the smallest adult pentastome known to date, represents the first record of a mammal as the definitive host of a cephalobaenid and may represent the only pentastome known to inhabit the lungs of a mammal through all its instars, with the exception of patent females. Adult males, non-gravid females and nymphs moulting to adults occur in the lungs; gravid females occur in the nasal sinus. R. petauri is minute and possesses morphological features primarily of the Cephalobaenida but the glands in the cephalothorax and the morphology of the copulatory spicules are similar to some members of the remaining pentastomid order, the Porocephalida. This unusual combination of features distinguish the new genus from other genera in the Cephalobaenida. The occurrence of only seven fully-formed larvae in eggs in the uterus, each representing about 10% of the length of the patent female, and her presence in the nasal sinus of a dependent juvenile P. breviceps (36 gm) implies a direct life cycle.

Towards a lower prevalence of Oestrus ovis infections in sheep in a temperate climate (south west France)

Oestrus ovis larvae are obligatory parasites of the nasal and sinus cavities of sheep and goats. In the temperate climate of western Europe, fly attacks occur between May and October and the first stage larvae arrest their development within the host between October and February. Oestrosis clinical signs such as nasal discharge and sneezing are well known by sheep breeders in southwest France. According to veterinarian recommendations, most of them treat their animals with long lasting fasciolicides once a year at least, mainly during the fly activity period and at the beginning of the hypobiotic period (when the parasitic population is only constituted of larvae). The consequences of these therapeutic programs were analysed in a local slaughterhouse by larval counts. Both prevalence and intensities of O. ovis infections decreased between 1989-1991 (before the use of systematic treatments) and 1996-1998 (after the spread of these treatments). The use of systematic treatments during the fly activity period and the beginning of the hypobiotic period seems to be very efficient in O. ovis control and could theoretically lead to a possible 'eradication' program as with cattle hypodermosis. Nevertheless the presence of parasites in apparently healthy goats, the possibility for a fly generation to develop before the first treatment in July-August and the succession of several fly generations all around the year in southern Mediterranean and tropical countries will maintain O. ovis infections. Furthermore, there are increased concerns about drug residues on consumer health and environment and this is the basis for the prospect of alternative strategies in O. ovis control.

Search for the trematode Prouterina wescotti in black bears in Oregon

Forty-six heads of free-ranging black bears (Ursus americanus) collected in May and June of 1995 and 1996 from Oregon (USA) were examined for the trematode Prouterina wescotti and other parasites. Only Sarcocystis sp. was detected in two adult male bears. Prouterina wescotti has been found only once previously in one black bear from Idaho (USA); its normal definitive host remains unknown.

Experimental infection of dogs with the nasal mite Pneumonyssoides caninum

A successful experimental transmission of the canine nasal mite, Pneumonyssoides caninum, is described. Some 11 weeks after repeated systemic ivermectin treatment, four Beagles were inoculated via the right nostril with 20 P. caninum mites of different sexes and life stages, obtained at the necropsy of an infected dog. The inoculated dogs and a matching uninoculated control were observed for clinical signs for 14 weeks and then euthanised. Vague upper respiratory signs and a transient minor increase in the number of eosinophils in peripheral blood were recorded in the inoculated dogs. At necropsy 4-12 P. caninum mites were found in the nasal cavities and sinuses of the inoculated dogs, but none in the control. In three out of the four infected dogs mites were found in both the right and left nasal cavities and sinuses of the skull. Since in no case more mites than the number used for inoculation were detected it is not clear if the mites managed to reproduce in the dogs. Inflammatory lesions were seen most consistently in the olfactory mucosa, respiratory mucosa and tonsils, and growth of opportunistic bacteria was observed in the tonsils of the infected dogs. The inflammatory lesions seen in the olfactory mucosa may explain why dogs infected with P. caninum sometimes appear to suffer from impaired scenting ability.

Prevalence and seasonality of Oestrus caucasicus Grunin, 1948 (Diptera: Oestridae) parasitizing the Spanish ibex, Capra pyrenaica (Mammalia: Artiodactyla)

Prevalence and intensity of parasitism by oestrid larvae in the Spanish ibex Capra pyrenaica were determined for a period of 2.5 yr in Sierra Nevada Natural Park, southern Spain. The most relevant result of this study was to find Oestrus caucasicus parasitizing this ungulate in a geographical location far from its previously known distribution, e.g., the Caucasus mountain range and central Asia. Larvae were found within 74% of the heads examined (n = 180). Prevalence was higher in females and in older animals. Lowest prevalence occurred during the summer months. The mean intensity (+/- SD) was 25.4 +/- 27.3 larvae and was similar in both host sexes. The number of larvae increased with host age and reached the highest intensities in winter, during December and January.

Prouterina wescotti n. gen., n. sp. (Trematoda: Prouterinidae N. Fam.) from the brain, lungs, and nasal sinuses of a black bear (Ursus americanus) from Idaho

Prouterina wescotti gen. n. and sp. n. (Trematoda: Prouterinidae N. Fam.) is described from a free-ranging black bear (Ursus americanus) which died in May 1995 in northern Idaho (USA). Adult digenetic trematodes were detected in brain, lungs, and nasal sinuses, and were likely responsible for the emaciated condition, copious nasal discharge, neurological signs, and death of the bear. Mature trematodes recovered from the bear were conical with small spines on the tegument. The anterior end was broad and tapered gradually toward the posterior. Mean (+/-SE) size of the mature trematodes was 3.67 (+/-0.08) by 2.14 (+/-0.04) mm (n = 80). Eggs are operculated, gold, and 68.2 (+/-0.42) by 41.4 (+/-0.41) microns (n = 75). Suckers are well developed and located in the anterior half of the body, with the genital pore just posterior to the ventral sucker. Testes are tandem and the ovary is lateral and slightly anterior to the anterior testes just posterior to the ventral sucker. The uterus is predominantly anterior to the ventral sucker and is the most distinctive feature of the trematode.

Chronic microsporidian infection of the nasal mucosae, sinuses and conjunctivae in HIV disease

A case of chronic infection of the nasal mucosae, sinuses and conjunctivae with a microsporidian parasite in association with HIV infection and immune deficiency is reported. This microsporidian resembles both Encephalitozoon cuniculi and the newly described Encephalitozoon hellem by electron microscopy. This occurred in an adult male resident in the UK with no history of foreign travel. Although there are previous descriptions of conjunctival infections from the USA, this is the first description of infection of the nasal epithelium. Further studies are underway to classify this protozoan.

Epidemiology of Oestrus ovis in southwest France

From July 1989 to June 1990, 555 heads of adult sheep obtained from Pamiers slaughterhouse (southwest France) were examined for infestation by Oestrus ovis. Infestation was present in 65% of the heads and the mean larval burden per positive case over the year was 24.8. The monthly prevalence rate varied from 44% in April to 88.2% in November. There are usually three generations of O. ovis each year: the first in March-April, the second in June-July and the last in September-October. There was no fly activity in winter and during the hottest months of summer. On the other hand, nearly all the larvae overwintered as the first stage. This study emphasizes the seriousness of the problem in the region and the authors recommend three strategic treatments per year during periods of high fly activity.

Recovery of helminths postmortem from equines. II. Helminths and larvae of gasterophilus in the gastro-intestinal tract and oestrids from the sinuses

The tongue, pharynx, oesophagus and gums are examined for larvae of gasterophilus spp., and the nose and sinuses for oestrid larvae. The gastro-intestinal tract is divided into separate specimens-stomach, small intestine, caecum, ventral colon, dorsal colon, descending colon and rectum- and each is examined separately. Aliquots of ingesta of 1/4 by mass of the stomach and 1/10 by mass of the small intestine, caecum, ventral colon and dorsal colon are collected for microscopic examination. Each part of the wall of the caecum, ventral and dorsal colon is washed and specimens are collected for subsequent examination. The gut wall of the caecum and colon is examined macroscopically for larval stages. Ingesta in the descending colon are examined macroscopically for Gasterophilus larvae.

Nasitrema attenuata (Trematoda) infection of Tursiops truncatus and its potentialities as an aetiological agent of chronic pulmonary lesions

Two cases of Nasitrema sp (Trematoda) infection of the bottlenosed dolphin, Tursiops truncatus, are reported and N. attenuata is briefly redescribed. The adults of the trematode occurring in the nasal sinuses and posterior nasal passage of the dolphins are considered as practically harmless for the host but thier eggs, aspirated deep into the bronchial tree, may initiate a foreign-body of inflammatory reaction in the lungs and continuous aspiration of such eggs may provoke a chronic pneumonia condition.