Two cases of enteric myiasis in man. Pseudomyiasis and true intestinal myiasis.

Dipterous larvae were found in the appendices from two postmortem examinations. The single maggot in the first case was not immediately identified in the sections. However, when the posterior end of the larva was recovered from the unsectioned portion of the appendix, it was identified as a maggot of the genus Sarcophaga. The first case was believed to be a case of "pseudomyiasis,+ i.e., the accidental entrapment of a swallowed larva passing through the digestive tract. In the second case, the appendix contained numerous larvae with great variation in sizes and stages of development of the mouth hooks, pharyngeal sclerites, and spiracular breathing plates. Such development was considered to have occurred within the intestinal tract, which indicated that this was a case of true intestinal myiasis.

Ophthalmomyiasis caused by the sheep nasal bot, Oestrus ovis (Oestridae) larvae, in the Benghazi area of Eastern Libya.

In a two-year study, from January 1977 to December 1978, 80 human cases of ophthalmomyiasis were recorded at the Benghazi Central Eye Clinic. Infections were due to larvae of the sheep nasal bot, Ostrus ovis. The annual incidence was estimated to be 10 per 100,000 population, with most of the cases occurring amongst males during the months of May, June and July. A typical case history is described to illustrate the clinical features and the treatment used.

Increasing horse fly (Diptera: Tabanidae) catch in canopy traps by reducing ultraviolet light reflectance.

Application of UV Killer, a commercially available product which reduced ultraviolet reflectance from cloth fabrics, increased the catch of tabanids in canopy traps by 24% and in CO2-baited traps by 30%. Catch decreased as ultraviolet reflectance increased during the experiment.

Identification of horse flies (Diptera: Tabanidae) by analysis of cuticular hydrocarbons.

Thin-layer chromatography of the cuticular lipids of horse flies from Oklahoma revealed that hydrocarbon was the major lipid class present. The hydrocarbon fraction was composed of n-alkanes and methyl branched alkanes with only a small amount of alkenes present. Gas chromatography of the isolated cuticular hydrocarbons from a single species, Tabanus abactor Philip, showed no major differences in the profiles between individuals or between the sexes. Analysis of extracts of fresh, frozen, and pinned specimens yielded nearly identical hydrocarbon profiles. Profiles of several species were examined and found to be unique for each. Three species with similar morphological characteristics and similar geographical ranges. Tabanus abdominalis F., T. limbatinevris Macquart, and T. sulcifrons Macquart, were differentiated easily by comparison of the hydrocarbon profiles.

Classification of screwworms (Diptera: Calliphoridae) by larval spine morphology.

The morphology of screwworm, Cochliomyia hominivorax (Coquerel), larval spines was affected by larval substrate and geographic effects on variation. Spine morphology of individual larvae was used to determine criteria for discrimination analysis classification. Classification criteria for types of wounds and host species were determined for larvae from central and southern Mexico. Larvae from marginal populations (United States, Caribbean Islands, Costa Rica) were classified by these criteria. Classifications were 27% accurate for wound type and 20% correct for animal species. When single egg masses were split and larvae were reared on laboratory diet and animal substrates, analysis of spine types showed significant rearing environment and sibship (egg mass) effects. Cluster analysis of geographic groups showed that larvae from central populations were closely clustered, whereas marginal groups were morphologically dissimilar from each other and from the central populations. These results indicate that larval spine morphology has limited value in taxonomic or systematic studies of screwworms and that mating compatibility was not related to spine similarity among populations. The significant differences between wound-reared and artificial media-reared larvae indicate that differences in spine morphology could be used to verify that samples from the field were indeed taken from animal wounds.

Facultative myiasis by Megaselia sp. (Diptera: Phoridae) in Texas: a case report.

Facultative myiasis caused by larval Megaselia sp. is reported in a human in Texas. On two occasions during 24 h, the youth experienced a "crawling sensation deep in [his] throat" which caused him to cough, expelling a living Megaselia sp. larva. The site of the infestation was presumed to be the sinuses or upper respiratory tract. The symptoms resolved upon expulsion of the larvae, and no additional complications were observed in the patient.

Urogenital myiasis caused by Megaselia scalaris (Diptera: Phoridae): a case report.

A case of urogenital myiasis in a patient with transverse myelitis is reported from Imphal, Manipur, India. The larvae of Megaselia scalaris Lowe were recovered repeatedly from the urine of the patient and were reared to adult to facilitate identification. This is the first known case of urinary myiasis caused by M. scalaris in India.

Myiasis in a wounded soldier returning from Panama.

An imported case of traumatic myiasis occurred in a soldier wounded during military action in Panama in December 1989 and evacuated to Brooke Army Medical Center, Fort Sam Houston, Texas. At the medical center, five larvae were removed from the scalp wound, reared to the adult stage, and identified as Cochliomyia hominivorax (Coquerel). Though this was the only reported case of wound myiasis of the 254 servicemen evacuated for medical treatment, this incident indicates a potential mechanism for the reintroduction of C. hominivorax into the United States.

Nosocomial nasal myiasis.

Sixty-five fly maggots were retrieved from the nasal cavity of an unconscious 64-year-old man who had been admitted 18 days earlier with diabetic hyperosmolar coma. The larvae were identified as Cochliomyia macellaria, an organism commonly associated with myiasis in the United States. The clinical time sequence indicates that this infection was acquired in the hospital. This incident provides further evidence that immobile and debilitated patients are at risk to acquire myiasis.

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.

The use of injectable rafoxanide against natural ovine nasal myiasis.

Rafoxanide (Flukanide), 7.5 mg kg-1 b.w. was administered to a group of 17 sheep naturally infected with Oestrus ovis larvae. A similar untreated control group was simultaneously observed for changes in clinical signs and body weights. Three animals from each group were slaughtered and examined for the presence of larval instars of O. ovis. While no larvae were recovered from the treated group, a total of 26 larvae, predominantly first and third instars, were recovered from nasal sinuses of the untreated group. There was clinical recovery and additional weight gain (+3.52 kg) after 2 months in the treated animals and a noticeable clinical deterioration of the untreated animals. The effect of the drug lasted for greater than 25 days.

Internal parasites of horses on mixed grassveld and bushveld in Transvaal, Republic of South Africa.

Between 1980 and 1982, the gastrointestinal tracts of 17 horses which had been grazing on mixed grassveld at Potchefstroom and bushveld at Onderstepoort in the province of Transvaal, Republic of South Africa, were examined at necropsy and processed for parasite recovery. The large strongyles and their prevalences were as follows: Strongylus vulgaris and associated lesions (88-94%), Strongylus edentatus (24%), Strongylus equinus (30%), Triodontophorus nipponicus (35%) and Craterostomum acuticaudatum (18%). The seven most prevalent and abundant cyathostomes collected were Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicostephanus calicatus, Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus minutus and Cyathostomum coronatum. Gasterophilus intestinalis was the most prevalent and abundant botfly larva recovered. Most of the cyathostome larvae and adults were present during all seasons except winter. The distribution of cyathostome species in the large intestine of the host is discussed.

Ectoparasites of sympatric cottontails (Sylvilagus audubonii Nelson) and jack rabbits (Lepus californicus Mearns) from the high plains of eastern New Mexico.

Eight species of ectoparasites were recovered from 35 Sylvilagus audubonii and 35 Lepus californicus occurring sympatrically near the Clovis-Portales area of eastern New Mexico. Recovered were Anoplura (Haemodipsus setoni), Diptera (Cuterebra lepusculi and Cuterebra ruficrus), Siphonaptera (Echidnophaga gallinacea and Euhoplopsyllus glacialis), and Acari (Ornithodoros parkeri, Dermacentor parumapertus, and Haemaphysalis leporispalustris). Jaccard's index showed a 50% ectoparasitic overlap with H. setoni, E. glacialis, D. parumapertus, and H. leporispalustris present on both host species. Cuterebra lepusculi, E. gallinacea, and Ornithodoros parkeri were taken only from S. audubonii, whereas C. ruficrus occurred only on jack rabbits. Euhoplopsyllus glacialis was the only species to demonstrate a preference for sex of host, occurring more abundantly on females.

Postembryonic development of Wohlfahrtia magnifica (Schiner, 1862) (Diptera: Sarcophagidae).

A description of the larval development of Wohlfahrtia magnifica (Schiner, 1862) is given. An interpretation of the morphological development correlated with functional and adaptive aspects of myiasis-causing flies is also included. A detailed analysis of morphological changes that occurred in W. magnifica larvae during postembryonic development is carried out. These changes happen in 2 larval interinstars, I-II and II-III, in which several structures such as anterior and posterior peritremes and cephalopharyngeal skeleton play an important role. The possible functions of these structures are considered. We also describe the first instar in W. magnifica to differentiate it from that belonging to Sarcophaga species, paying special attention to disposition of the cephalopharyngeal skeleton, anterior peritremes, and spinulation on the last 3 segments. Several structures, not described previously in Sarcophagidae, were observed: modified spines of the buccal and peritremal cavities, peritremal tubercles, and modified spines on the ventral surface. Changes occurring in these structures during larval development are described. Their probable role in the taxonomy of the genus Wohlfahrtia and their application to Nearctic species belonging to this genus, Wohlfahrtia vigil and Wohlfahrtia opaca, are also discussed.

Variation in skin inflammatory responses between sheep bred for resistance or susceptibility to fleece rot and blowfly strike.

Sheep which have been bred for resistance (R) or susceptibility (S) to fleece rot and blowfly strike, were tested for intradermal inflammatory responses to excretory and secretory products of Lucilia cuprina larvae. R rams and lambs gave significantly larger skin weals than S animals. In addition, R and S rams were infected with L cuprina first instar larvae and wound exudates were collected. In the first 12 hours of infection R rams released significantly more exudate protein at the wound site than S rams. Correlations suggested that exudate production was stimulated by both larval burden and inflammatory responses, however, in the R group the inflammatory correlation was positive while in the S group it was negative. The results imply that inflammatory responses may play a role in innate resistance to L cuprina. The difference in inflammatory responses suggests genetic differences between the flocks and therefore could show some potential as a trait for indirect selection for resistance to fleece rot and body strike.

[Infestation of roe deer by Cephenemyia stimulator (Clark) (Diptera, Oestridae) in Trent province]. / Infestazione di caprioli ad opera di Cephenemyia stimulator (Clark) (Diptra, Oestridae) in provincia di Trento.

Cephenemya stimulator (Clark) (Diptera Oestridae) is first recorded in Italy parasiting roe deer (Capreolus capreolus). Diagnosis was made by examination of II-III instar larvae (fig. 1-2) from roe deers killed in Trient province. In these last years in the Trentin region, there was an increasing of roe deers number (actually about 20.000); at the same time growed roe deers infestation by C. stimulator (Tab. 1). Females of C. stimulator probably attack young roe-deers lying down on field-pastures near forest (fig. 3). From examination of killed roe-deers (Tab. 2) there is evidence of debilitation status of infested specimens. Location and dislocations of parasitising larvae in the head cavity was that shown in fig. 4 and 5.

Infection by the warble fly Przhevalskiana silenus Brauer, 1858, in the Italian goats. An update up to 1988.

This paper is a review of the work done at the University of Bari on the goat warble fly Przhevalskiana silenus Brauer, 1858. It reports data concerning taxonomy, biology, and epidemiology of the goat warble fly, as well as therapy against the infection. Grunin in 1962, and later Madel in 1969, were the first researchers to reach the conclusion that the three species of Przhevalskiana up to then recognized--namely P. silenus, P. aegagri, and P. crossii--should be unified in just one--Przhevalskiana silenus. The genetical studies conducted by us on the third instar larvae with the use of 9 gene-enzyme systems confirmed the assumption that P. silenus is the only species which parasitizes goats. Studies were conducted on the external life-cycle of the parasite with the purpose of elucidating the relationship existing among time of dropping, length of time needed for adults to emerge from pupae, and temperature of the environment. Both total sum of temperature and length of time seem to play an important role in determining the duration of the pupal stage. Epidemiological data derived from a two-year survey carried out in six infected groups of goats are also reported. The interrelationship existing among prevalence, mean intensity, variance, variance/mean rate, and parameter K of the negative binomial are presented. It appears that age, parameter K, and variance of infection intensity are closely related. A trial experiment was also carried out to evaluate the efficacy of ivermectin against a natural infection with P. silenus larvae. A single subcutaneous injection of 1% ivermectin was given, at doses of 50, 100 or 200 micrograms/kg b.w. The drug was found to be fully effective at all three doses.

External ophthalmomyiasis associated with herpes zoster ophthalmicus.

Ophthalmomyiasis is a rare entity caused by infestation with certain dipterous larvae. We describe a 71-year-old farmer with herpes zoster ophthalmicus on the left side of the face in whom the blisters became secondarily infested with Chrysomyia bezziana maggots. The maggots were removed mechanically, and the corneal involvement secondary to zoster ophthalmicus responded to therapy with topical steroids and cycloplegics. To our knowledge this is the first report of external ophthalmomyiasis due to C. bezziana.

Synanthropy of Anthomyiidae, Muscidae and Calliphoridae (Diptera) in Cuba.

The material of 22302 flies of Anthomyiidae, Muscidae and Calliphoridae collected by trap-method in Cuba 1966 was qualitatively and quantitatively analysed. Relative density, seasonal incidence and food preference were ascertained in 20 species. In potential vectors of human diseases the ecological characters and classification of synanthropy are given.

Studies on the low and fundamental populations of the warble fly Hypoderma bovis (De Geer) (Diptera, Hypodermatidae).

During control measures against cattle hypodermatosis low populations of warble flies with incidence of infestation (extensity, percentage) up to 2-5% persist after a rapid decrease of the degree of infestation. In order to study these low populations isolated warble fly populations were experimentally created under conditions of Central Europe. Fundamental populations observed originated from one ovipositing female in a herd of heifers and included 17, 25, 42 and 83 larvae with 11-52% of infestation and mean infestation of 1.1-1.6 larvae per infested host (intensity of infestation). With the increasing age of heifers from one to 2.5 years the numbers of fundamental populations decreased to one quarter, the extensity of infestation to one fifth, while the mean infestation per infested host remained nearly at the same level. The persistence of low warble fly populations was caused by an internal system regulating the numbers of parasites in the host populations. The distribution of larvae of fundamental warble fly population in a cattle herd agrees with the Poisson distribution as well as the negative binomial distribution. The direct significance of the results obtained for the control of hypodermatosis is pointed out.