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At least 19 recordsLinked to original sources
PubMed1993

An unusual nosocomial infection: nasotracheal myiasis.

A number of fly maggots were found emerging from the nose and tracheostomy site of an 82-year-old woman who had been in a coma for two months in an acute care hospital in a large Canadian city. This case history indicates that the infestation was hospital-acquired and although undoubtedly an extremely rare occurrence, at least in Canada, points out the risk of myiasis in the unconscious, debilitated patient.

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PubMed2004

Orbital myiasis in a patient with a chronically exposed hydroxyapatite implant.

We describe the clinical presentation of the first case, to our knowledge, of myiasis in an orbit with an exposed hydroxyapatite implant. We examined a 10-year-old boy with an 8-year exposure of an orbital implant. He had an infestation with maggots. The implant and the worms were surgically removed, allowing the socket to heal by secondary intention. The patient was able to wear a prosthesis 2 weeks later. The parasites were identified as belonging to Cochliomyia hominivorax, a fly responsible for the majority of cases of myiasis in the Western hemisphere.

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PubMed1986

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.

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PubMed2005

Unusual cases of human myiasis due to Old World screwworm fly acquired indoors in Hong Kong.

Myiasis is the infestation of tissue by the larvae of flies. We report eight cases of human myiasis in Hong Kong. All patients were nursing home residents with an average age of 81.8 years. Seven patients were bedridden with advanced dementia. Four patients had pre-existing wounds. Five had poor oral hygiene and four of those were on tube feeding. All of the five patients with poor oral hygiene suffered from oral myiasis. Two patients had vaginal infestations and one had wound myiasis in his diabetic foot ulcer. Seven cases were infested by Chrysomya bezziana, an obligatory parasite that requires living mammalian tissue for its larval development. Larvae of the Calliphoridae family were responsible for the remaining case. Patients were managed with manual removal of larvae and irrigation of the site of infestation with saline. All infestations were nosocomial, being acquired in nursing homes. Carers of the old and debilitated should be made aware of the need for better oral care, especially for those on tube feeding. The use of window screens in nursing homes should be encouraged to reduce the chance of flies entering the vicinity of these patients. Electrocuters could also be mounted indoors to kill flies that do enter.

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PubMed1993

Prophylactic and persistent efficacy of doramectin against Cochliomyia hominivorax in cattle.

Two prophylactic studies and one persistent efficacy study were conducted in Brazil to evaluate one injection of doramectin at a dose rate of 200 micrograms kg-1 against induced infestations of the New World screwworm, Cochliomyia hominivorax. In each prophylactic study, 12 calves were allocated to two groups of six animals. Six calves were treated with doramectin and six with saline. Two hours after treatment, animals were anesthetized and received two incisions, one in the shoulder and one in the rump. Each incision was then infested with 50 first instar larvae. In the persistent efficacy study, 24 calves were allocated to six groups (T1-T6) of four animals each. On the day of treatment, three groups (T1, T3 and T5) were treated with saline and three groups (T2, T4 and T6) with doramectin. All animals were anesthetized and received four incisions, one in the shoulder and one in the rump of each side. Each incision was then infested with 30 first instar larvae of C. hominivorax with the following schedule: T1 and T2 at Day 3, T3 and T4 at Day 7, and T5 and T6 at Day 14 post-treatment. Calves were observed daily and incisions evaluated for 8 days post-infection. Larvae that completed development and exited the wounds were collected and incubated to evaluate viability. In all experiments, doramectin was 100% efficacious in preventing screwworm infestation caused by field isolates of C. hominivorax. First instar larvae were eliminated from the incisions of doramectin-treated calves between 24 and 48 h post-treatment, and no third instar were recovered at any time. As a consequence, healing started at 24 h and was completed at 96-120 h post-infection. Screwworm infestations and viable third-instar larvae developed in all the incisions in non-treated calves, and healing did not begin until larvae had completed their normal life cycle and exited the wounds. The persistent efficacy of a single injection of doramectin extended beyond 14 days.

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PubMed1991

Oviposition by screwworm flies (Diptera: Calliphoridae) on contact with host fluids.

Factor affecting oviposition by screwworm flies, Cochliomyia hominivorax (Coquerel), contacting different host fluids were examined in a laboratory bioassay. Fresh bovine blood, which does not release the attractive odors involved in host finding, nevertheless stimulated as many or more females to oviposit than did the other fluids tested. These other fluids included attractive fluid from screwworm-infected wounds (a favored oviposition site in nature) and cultures of Providencia rettgeri (a bacterium implicated in attractant production). Oviposition did not vary with batch of fresh blood or frozen storage, making blood a useful standard for comparing oviposition rates among studies. Oviposition did vary with the substrate to which the blood was applied, suggesting that an interaction between tactile and chemical stimuli is important for host recognition. Both insemination and darkness during bioassay increased oviposition rates, but the magnitude of these effects was small compared with that due to substrate. Age had no effect for at least 1 wk after females became gravid.

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PubMed1991

Studies on the screwworm fly Cochliomyia hominivorax in Libya: effect of temperature on pupation and eclosion.

The American screwworm fly Cochliomyia hominivorax has recently been reported in Libya (El-Azazy 1989). Fly larvae were cultured on blood agar at different temperatures (-5 degrees, 5 degrees, 18 degrees, 20 degrees, 30 degrees, 37 degrees, or 40 degrees C). Larvae pupated at 18 degrees, 20 degrees, 30 degrees, or 37 degrees C, and the highest pupation (100%) occurred at 20 degrees C. Adult flies emerged from pupae that were maintained at 18 degrees, 20 degrees, 30 degrees, or 37 degrees C; the maximal eclosion (94%) occurred at 20 degrees C. Correlation of these findings with meteorological temperature data from local areas in which C. hominivorax myiasis occurs suggests a crucial role for temperature in the determination of the effective environment for this fly species.

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PubMed2006

Genetic approaches for studying myiasis-causing flies: molecular markers and mitochondrial genomics.

"Myiasis-causing flies" is a generic term that includes species from numerous dipteran families, mainly Calliphoridae and Oestridae, of which blowflies, screwworm flies and botflies are among the most important. This group of flies is characterized by the ability of their larvae to develop in animal flesh. When the host is a live vertebrate, such parasitism by dipterous larvae is known as primary myiasis. Myiasis-causing flies can be classified as saprophagous (free-living species), facultative or obligate parasites. Many of these flies are of great medical and veterinary importance in Brazil because of their role as key livestock insect-pests and vectors of pathogens, in addition to being considered important legal evidence in forensic entomology. The characterization of myiasis-causing flies using molecular markers to study mtDNA (by RFLP) and nuclear DNA (by RAPD and microsatellite) has been used to identify the evolutionary mechanisms responsible for specific patterns of genetic variability. These approaches have been successfully used to analyze the population structures of the New World screwworm fly Cochliomyia hominivorax and the botfly Dermatobia hominis. In this review, various aspects of the organization, evolution and potential applications of the mitochondrial genome of myiasis-causing flies in Brazil, and the analysis of nuclear markers in genetic studies of populations, are discussed.

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PubMed1985

Current trends in screwworm myiasis in the Caribbean region.

In a random sample of animal producers and animal health personnel, 33% of the respondents in Trinidad, 15% in Guyana, 11% in Suriname and 9% in Jamaica recalled at least one case of human myiasis due to Cochliomyia homivorax (Coquerel). During 1981, respondents in Surinam (88%), Jamaica (90%), Guyana (85%) and Trinidad and Tobago (82%) found at least one case of myiasis in their livestock, occurring mainly in cattle, pigs and dogs. Feral animals, e.g. jaguars, were also found to be infested. The initial wounds were mainly the umbilicus of neonates, and arbitrary wounds, and vampire bites were also affected. Fifty-three to 78% of all respondents examined their livestock daily for wounds and infestation by the screwworm. Annual estimates of losses (in U.S. dollars) due to surveillance and medication ranged from $4.82 to $10.71 per animal. Nationally, these losses amount to $0.30 million (Surinam), $1.02 million (Trinidad and Tobago), $4.33 million (Guyana) and $6.78 million (Jamaica). Figures for other losses, arising from failure to thrive, reduction in milk production and hide injury due to screwworm activity were not available. Most producers found that the greatest screwworm infestation occurred in the wet season, and most described it as second in importance to Boophilus spp. ticks as a pest of livestock, but of greater significance than biting flies, such as tabanids and stable flies. Eradication of the screwworm from the islands of Jamaica and Trinidad and Tobago can be recommended, but in Surinam and Guyana eradication seems feasible only on the 100-km wide coastal strips where most human and livestock populations exist.

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PubMed1992

Observations on the New World screwworm fly in Libya and the risk of its entrance into Egypt.

Data on traumatic myiasis caused by Cochliomyia hominivorax in Libya were reported from August 1988 until February 1989. A total of 468 cases of screwworm myiasis were recorded in seven species of livestock and 229 humans, mainly children, were also found to be infested. Cattle and sheep were the most common hosts in livestock. In cattle, the principal infestation site was the umbilicus of neonates; in sheep, it was mainly the fatty tail. Animal myiasis reached its peak in October and November, but disappeared abruptly in winter on the onset of cold weather. Screwworm distribution was confined to the northwest of Libya. The potential dispersion of the fly from this area and the possibility of infestation of other countries, particularly Egypt, are discussed. Food and Agriculture Organization (FAO) efforts to confront the New World screwworm problem in Africa are mentioned.

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PubMed1995

Efficacy of doramectin in the protection of neonatal calves and post-parturient cows against field strikes of Cochliomyia hominivorax.

Two studies were conducted in Latin America, one in Venezuela and one in Argentina, using a common protocol to investigate the efficacy of a single s.c. injection of doramectin in the prevention and control of field infestations of Cochliomyia hominivorax in newborn calves and post-parturient cows. In both experiments, pregnant cows were paired on the basis of their calving time. The first cow that calved was assigned to a medicated group, and both cow and calf were treated with doramectin. The cow received a dose of 200 micrograms kg-1 and the calf 1 ml of a 1% doramectin solution. The second cow and calf were assigned to a saline-treated group, and the cow received saline at 1 ml per 50 kg and the calf 1 ml. The procedure was repeated until all animals were allocated to the two treatments. Animals were examined on the treatment day and at 2, 4, 6 and 12 days post-treatment. At each observation day, the navel of newborn calves and external genitalia of the cows were inspected and the presence of C. hominivorax infestations was recorded. Doramectin was 100% effective in the prevention and control of screwworm strikes in newborn calves and in post-parturient cows exposed to continuous field challenge of C. hominivorax. Over the 12 day duration of the studies, 48% and 57% of the saline-treated calves had screwworm navel strikes in the studies in Venezuela and Argentina, respectively. Infested animals required repeated therapeutic treatment, whereas none of the doramectin-treated calves were affected (P < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1995

Efficacy of injectable doramectin in the protection of castrated cattle against field infestations of Cochliomyia hominivorax.

Three studies were conducted in Latin America--one in Venezuela, one in Argentina and one in Brazil--using a common protocol to investigate the efficacy of a single subcutaneous injection of doramectin in the prevention and control of Cochliomyia hominivorax infestations in castrated cattle. In each study, two groups of 20-28 animals each were allocated to a treated (T1) or to a control (T2) group on the basis of body weights. Animals of T1 received doramectin at 200 micrograms kg-1 (1 ml per 50 kg) and animals of T2 received saline solution at 1 ml per 50 kg of live weight. After treatment all cattle were castrated surgically. Animals were examined on treatment day and at 2, 4, 6 and 12 days post-treatment. At each observation day, the presence of C. hominivorax infestations was recorded. Doramectin was 100% effective in the prevention and control of screwworm strikes in castrated cattle exposed to continuous field infestations of C. hominivorax in tropical and subtropical areas of Latin America. Over the 12 day duration of the studies, 85%, 60% and 65% of animals in the control groups had infested wounds in Venezuela, Argentina and Brazil, respectively. Affected animals required repeated therapeutic treatment, whereas none of the doramectin-treated cattle were infested (P < 0.0001). A high proportion of the castration wounds in doramectin-treated cattle had the presence of characteristic C. hominivorax eggs but none developed into larvae. There were no clinical signs of adverse reactions to treatment in any of the three studies.

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