Oestridae Research Articles

Sebaceous cysts with unpleasant twists: cutaneous myiasis with Dermatobia hominis

Dermatobia hominis (human Bot fly) causes furuncular myiasis (larval infection) in Central and South America. This report describes a case in a member of the UK Armed Forces who had recently taken part in an overseas training exercise in Belize. The importance of clinical history (including travel history) is highlighted. We also describe the outcomes of conservative treatment and surgical intervention for separate lesions in the same patient.

Cephenemyia stimulator and Hypoderma diana infection of roe deer in the Czech Republic over an 8-year period

A survey of naso-pharyngeal and subcutaneous myiasis affecting roe deer (Capreolus capreolus) was conducted in the Czech Republic over an 8-year period (1999-2006). A total of 503 bucks and 264 does from six hunting localities were examined. The sampling area comprised predominantly agricultural lowlands and a mountain range primarily covered by forest. Since 1997, the deer have been treated each winter across the board with ivermectin (150 mg/kg, CERMIX® pulvis, Biopharm, CZ). Parasites found were the larvae of Hypoderma diana and Cephenemyia stimulator. There were no significant differences in warble fly infection among captured animals in the individual hunting localities. Overall, 146 (28.8%) of 503 animals (bucks) were infected with Cephenemyia stimulator larvae; body size of the second instar larva reached 13-18 mm. The prevalence ranged from 16.1 to 42.9% per year, and the mean intensity from 6 to 11 larvae per animal. Additionally, a total of 264 roe deer (does) were examined for H. diana larvae, and 77 (29.1%) were found to be positive; body size of the second instar larva reached 17 mm. The prevalence ranged from 18.8 to 50.0% per year, and the mean intensity from 13 to 22 larvae per animal. The results showed that the bot flies, Cephenemyia stimulator as well as H. diana, are common parasites in roe deer in the Czech Republic, and that through the help of treatment (ivermectin), it is possible to keep parasite levels low. The body weights of infected and non-infected H. diana deer did not differ significantly.

Philornis sp. bot fly larvae in free living scarlet macaw nestlings and a new technique for their extraction

Bot fly larvae (Philornis genus) are obligate subcutaneous blood-feeding parasites of Neotropical birds including psittacines. We analyze twelve years of data on scarlet macaw (Ara macao) nestlings in natural and artificial nests in the lowland forests of southeastern Peru and report prevalence and intensity of Philornis parasitism. Bot fly prevalence was 28.9% while mean intensity was 5.0 larvae per infected chick. Prevalence in natural nests (11%, N=90 nestlings) was lower than in wooden nest-boxes (39%, N=57) and PVC boxes (39%, N=109). We describe a new technique of removing Philornis larvae using a reverse syringe design snake bite extractor. We compare this new technique to two other methods for removing bots from macaw chicks and find the new method the most suitable.

Essays on the history of brazilian dipterology: III. Three remarkable notices from the 18th century, mainly related to myiasis-producing flies (Cochliomyia and Dermatobia)

This paper registers reports about dipterans made by three Portuguese who lived in Brazil during the 18th century. Luiz Gomes Ferreira, in his book Erario mineral [Mineral revenue], wrote curious passages related with myiasis-causing flies of the genus Cochliomyia. Jose Rodrigues de Mello registered, in Latin verses, the folklore for curing myiases caused by Cochliomyia hominivorax in cattle. Luiz dos Santos Vilhena, in the last of his twenty letters dealing with several aspects of life in Brazil, made reference to horseflies, human bot flies and mosquitos.

Risk‐spreading larviposition behaviour of female nose bot flies (Cephenemyia) attacking black‐tailed deer

While baited deer models were under observation nine Cephenemyia jellisoni Townsend (Diptera: Oestridae) females and seven C. apicata Bennett & Sabrosky engaged in a risk-spreading larviposition behaviour by larvipositing on models only once and then flying away. Additionally, analysis of 225 unobserved larvipostions in which larvae were trapped in adhesive on the muzzles of deer models showed that 94% of C. apicata and 95% of C. jellisoni larviposited on a model only once. The number of single larvipositions was highly significant for both species. The principal adaptive significance of such risk-spreading larviposition behaviour is that it spreads the reproductive output of a female among many hosts, and in years when adult eclosion and survival rates are low, it ensures that the larvae of the few surviving females will be distributed among a maximum number of hosts. Several other benefits of such behaviour also are discussed.

Prevalence study in horses infected by Gasterophilus sp. in an eastern region of Poland

A survey to determine current prevalence of Gasterophilus spp. (bot flies) in equids (n=400) at necropsy in slaughtered horses was conducted at the abattoir in Rawicz. The evaluation was performed according to sex, age, larval stages, severity of infestation and localization, respectively. Only Gasterophilus intestinalis and Gasterophilus nasalis were detected. The prevalence determined in the eastern part of Poland was of 47%. The high prevalence of this parasite infection in the Polish horse population confirms that Gasterophilosis spp. has to be taken into serious consideration and prophylactic measures might be indicated.

Characteristics of roe deer bot fly infection in the southern part of the Great Hungarian Plain

I am investigating the occurance of one of the diseases caused by parasites in plain roe deer populations, namely a botfly larvae, Cephenemyiastimulator, (Clark, 1815) ranged among the Oestridae family. Nasal botfly larvae are common roe deer parasites and are generally spread nationwide. The subject of the present survey is the processing of the data gained about roe deer bucks of the year 2009 and their infestation indices. I investigated botfly larvae in 90 bucks’ nasal and pharyngeal cavity. We have found botfly larva in 18.9% of the examined bucks (prevalence), this means 17 infected specimen. I collected 218 pieces of larvae from the samples, with a 12.8 pieces average intensity. In my investigations prevalence was lower and mean intensity was higher than in previous Hungarian researches. This was manifested both in my overall data, and in our examinations by the different age groups.

First Report of Bot Fly (Cuterebra baeri) Infestation in Howler Monkeys (Alouatta palliata) from Mexico

We analyzed seven bot fly larvae extracted from six howler monkeys (Alouatta palliata) in Los Tuxtlas, Mexico. The spine distribution and structure of the larvae were consistent with those reported for Cuterebra baeri from Panama. This report sets the northern limit for its distribution in the Americas.

Free-ranging eastern chipmunks (Tamias striatus) infected with bot fly (Cuterebra emasculator) larvae have higher resting but lower maximum metabolism

Given the ubiquity and evolutionary importance of parasites, their effect on the energy budget of mammals remains surprisingly unclear. The eastern chipmunk ( Tamias striatus (L., 1758)) is a burrowing rodent that is commonly infected by cuterebrid bot fly ( Cuterebra emasculator Fitch, 1856) larvae. We measured resting metabolic rate (RMR) and cold-induced Vo2-max (under heliox atmosphere) in 20 free-ranging individuals, of which 4 individuals were infected by one or two larva. We found that RMR was significantly higher in chipmunks infected by bot fly larvae (mean ± SE = 0.88 ± 0.05 W) than in uninfected individuals (0.74 ± 0.02 W). In contrast, Vo2-max was significantly lower in chipmunks infected by bot fly larvae (4.96 ± 0.70 W) than in uninfected individuals (6.37 ± 0.16 W). Consequently, the aerobic scope (ratio of Vo2-max to RMR) was negatively correlated with the number of bot fly larvae (infected individuals = 5.74 ± 1.03 W; noninfected individuals = 8.67 ± 0.26 W). Finally, after accounting for the effects of body mass and bot fly parasitism on RMR and Vo2-max, there was no correlation between the two variables among individuals within our population. In addition to providing the first estimate of Vo2-max in T. striatus, these results offer additional evidence that bot fly parasitism has significant impacts on the metabolic ecology of this host species.

Sensilla on the antennal funiculus of the horse stomach bot fly, Gasterophilus nigricornis

Gasterophilus nigricornis (Loew) (Diptera: Oestridae) is one of the most damaging obligate parasites of equids in Kalamaili, Xinjiang, China. The main olfactory organs of this stomach bot fly are paired antennae that bear microscopic sensillar structures. The external morphology of the antennal funiculus and sensilla of male G. nigricornis were studied using stereopic microscopy and scanning electron microscopy. A cross-sectional view of the funiculus shows it to be triangular, with an anterodorsal surface, a dorsolateral margin and a posteroventral surface. Almost the entire surface of the funiculus is densely covered with microtrichiae. Small patches lacking these microtrichiae appear as depressions or pits in the surface of the funiculus. Six distinct types of sensilla are recorded, including one trichoid, three basiconic, one auriculate and one clavate sensilla. Trichoid sensilla are the most abundant, followed by the basiconic, auriculate and clavate types in descending order. Only auriculate sensilla are found in pits on the funiculus. Distributions of different sensilla types located on the antennal funiculus are provided. These results are compared with equivalent findings in several other fly species. In addition, the possible functions of the various sensilla types are discussed.

Myiasis among slaughtered animals in Kashan, Iran: describing a veterinary entomological problem in the tropics.

Myiasis is a common veterinary entomology problem in many slaughterhouses in the tropics.The prevalence of myiasis among slaughtered cattlewas investigated in Kashan Abattoir, central Iran, in 2009. All kinds of dipterous larvae that may cause myiasis were collected and identified.Thenthe prevalence of each infestation was analyzed by statistical tests. The results of the study revealed a total of 4 species of dipterous larvae belonged to two families of Sarcophagidae and Oestridae. The identified species were the following ones: Family Oestridae: Hypodermalineatum (61.4%), Hypodermaovis (12.6%), Oestrusovis (22.7%) and Family Sarcophagidae: Wohlfahrtiamagnifica (3.8%).Of the 7736 examined animals, 2.5% of goats and 0.5% of sheep were infested by any kinds of dipterous larvae. Statistical comparisons were made between the sex of host species and occurrence of myiasis, infested animals and species of larvae, the infested body parts of the host, and finally between the prevalence and origin of the cattle. Statistically the possibility of infestation of goats was 1.43 times more than sheep (odds ratio=1.43). These findingscan be considered by officials to keep the human and animal myiasis under control. There is also need to investigate the prevalence and incidence of animal myiasis in other parts of the country to clarify the spread of infestation in the country and in the region.

Corrected misidentification of first instars of the bot flies Cephenemyia apicata and C. jellisoni, with a review of the biology and life history of both species

First instars obtained from the uteri of host-seeking females, and compared with previously published descriptions of larvae collected from Columbian black-tailed deer (Odocoileus hemionus columbianus), revealed that larvae described as Cephenemyia apicata Bennett & Sabrosky (Diptera: Oestridae) actually are C. jellisoni Townsend. Several new characters are added to supplement the original descriptions of the first instars of these species. Collections of all larvae from deer autopsied during different months established that the first instars of C. apicata undergo a long obligate period of development and growth in the bronchi before molting and migrating to the retropharyngeal pouches of deer. This is the first study to document an obligatory lung phase in the life history of a species of Cephenemyia. The lung phase of C. apicata is compared with that described for Pharyngomyia picta (Meigen) (Diptera: Oestridae) in European red deer. A literature review found that for all Cephenemyia species studied, as well as for P. picta, a 6-8 month period of development as first instars during the fall/winter months ensures that pupal development and eclosion of adults will occur during periods of favourable external environmental conditions.

Parasites and vector-borne pathogens of southern plains woodrats (Neotoma micropus) from southern Texas

From 2008 to 2010, southern plains woodrats (Neotoma micropus) from southern Texas, were examined for parasites and selected pathogens. Eight helminth species were recovered from 97 woodrats including, Trichuris neotomae from 78 (prevalence = 80%), Ascarops sp. from 42 (43%), Nematodirus neotoma from 31 (32%), Raillietina sp. from nine (9%), Taenia taeniaeformis larvae from eight (8%), and an unidentified spiurid, a Scaphiostomum sp. and a Zonorchis sp. each from a single woodrat. Besnotia neotomofelis was detected in three (3%) woodrats and microfilaria were detected in seven (7%). Polymerase chain reaction (PCR) testing of blood samples from 104 woodrats detected a novel Babesia sp. in one (1%) and Hepatozoon sp. in 17 (16%) woodrats. Partial 18S rRNA gene sequence of the Babesia was 94% similar to B. conradae. Histologic examination of tissues detected intestinal coccidia in seven of 104 (7%), Sarcocystis neotomafelis in 26 (25%), Hepatozoon sp. in 21 (20%), and Dunnifilaria meningica in four (4%) woodrats. Three woodrats (5%) were seropositive for Toxoplasma gondii. Ectoparasites recovered included fleas (Orchopeas sexdentatus and O. neotomae), ticks (Ixodes woodi and Ornithodoros turicata), mites (Trombicula sp. and Ornithonyssus (Bdellonyssus) bacoti) and bot flies (Cuterebra sp.). The only difference in prevalence related to gender was for N. neotoma (males > females, p = 0.029). Prevalence of T. neotomae and all intestinal parasites combined was significantly higher in adults compared with juveniles (p = 0.0068 and p =0.0004), respectively. Lesions or clinical signs were associated with Cuterebra and B. neotomofelis. Collectively, these data indicate that woodrats from southern Texas harbor several parasites of veterinary and/or medical importance.

A review of comparative aspects of myiasis in goats and sheep in Europe

Myiasis is the infestation of living vertebrate animals and humans by the larvae of certain fly species (Diptera), which feed on the host's living or dead tissues and body fluids. Myiasis in sheep and goats is a major animal welfare issue causing considerable pain and suffering and, if untreated, can result in serious tissue injury, productivity losses, reproduction losses and death. A number of oestrid flies cause myiasis of sheep and goats. These include the goat warble flies (Przhevalskiana silenus), and the sheep nasal bot flies (Oestrus ovis). P. silenus has been reported mainly from goats. In contrast, infection rates and larval burdens with O. ovis are generally higher in sheep than goats, following both natural and artificial infestations, despite the fact that both ruminant species can act as hosts. Traumatic or wound myiasis is caused mainly by calliphorid and sarcophagid flies. Most of the calliphorid species involved, such as Lucilia sericata and Chrysomya albiceps, are facultative parasites. The single obligate parasite causing traumatic myiasis of goats and sheep in Europe is the sarcophagid, Wohlfahrtia magnifica, Wohlfahrt's wound myiasis fly. All calliphorids and sarcophagids can infest sheep and goats and there is no known predisposition of certain genetic types for different hosts. Myiasis causing parasites are found worldwide and are especially widespread in the countries of Europe and Africa bordering the Mediterranean Basin. Because of the milk oriented husbandry systems applied in those areas, prevention and control of myiasis can be problematic, especially of lactating females in sheep and goat herds, due to the lengthy withdrawal periods for many of the insecticidal products. Like many other pest species, global warming could enable them to move northwards in Europe, with damaging consequences for the naïve hosts that would thereby be exposed.

Parasitism by Oestrus ovis: Influence of sheep breed and nematode infections

Previous studies showed that Santa Ines (SI) hair sheep were more resistant to gastrointestinal nematode infections (GIN) than Ile de France (IF) sheep. The present experiment aimed to evaluate if that reported resistance difference against GIN also occurred against Oestrus ovis infestation and also to evaluate the influence of O. ovis infestation on the gastrointestinal nematodes (GIN) infections. SI (n=12) and IF (n=12) young male lambs were weaned at 2 months of age and moved to a paddock (0.3ha) with Brachiaria decumbens grass, where they also received concentrate ration. The animals were kept together during the experimental period (September to early December 2009). Fecal and blood samples were taken from all animals every 2 weeks and body weight and nasal discharge score (oestrosis clinic signs) were recorded on the same occasion. In early December 2009, all lambs were sacrificed and O. ovis larvae and GIN were recovered, counted and identified according to the larval stage. All animals were infested by different larval instars of O. ovis without any statistical difference between breeds (P>0.05). The SI lambs had an average of 24.8 larvae, and the intensity of infection ranged between 14 and 39 larvae, while the IF lambs showed an average of 23.5 larvae with the minimum and maximum from 11 to 36 larvae, respectively. SI lambs presented the lowest nematode fecal egg counts (FECs) and the lowest mean numbers of Haemonchus contortus, Trichostrongylus colubriformis and Strongyloides papillosus, however, there was no significant differences between group means (P>0.05). Inverse relationship between numbers of O. ovis larvae and gastrointestinal nematodes was observed in both breeds. SI sheep showed a significant increase in blood eosinophils and total IgE serum levels and these variables were negatively correlated with nematode FEC. A negative correlation was observed between total IgE serum level and H. contortus burden in both breeds. In conclusion, there was no breed difference regarding O. ovis infestation and in each breed, animals with more nasal bot fly larvae tended to display smaller worm burden.

Cuterebrid Myiasis (Diptera: Oestridae) in Captive Ring-Tailed Lemurs (Lemur catta) at a South Carolina Zoo

In September 2008, two ring-tailed lemurs (Lemur catta), comprising a mother-daughter pair, at the Greenville Zoo, Greenville, South Carolina, USA, were diagnosed with cuterebrid myiasis (Diptera: Oestridae) subsequent to sudden death of the adult lemur. On necropsy, a single bot warble was discovered in the subcutis of the axillary region. Histopathology revealed a severe eosinophilic bronchopneumonia. The juvenile lemur was inspected and found to have warbles on three separate dates in late September. One representative bot fly larva was identified as a Cuterebra sp. that normally infests lagomorphs in the southeastern United States. Cuterebrid myiasis is rarely reported in lemurs and has not been previously associated with pneumonia or death in these animals.

Nasal myiasis by Oestrus ovis second stage larva in an immunocompetent man: case report and literature review

We report a case of an Oestrus ovis larva which developed into the second larval stage within a healthy, immunocompetent human, and we review the relevant literature. Clinical case report and Pubmed search of reports of human nasal myiasis due to Oestrus ovis, especially those describing the larval stage. Humans are not normally hosts of the sheep nasal bot fly, but infestations by its larvae have been described. The eye is the most common site, but larvae have occasionally been found in the human nose. Transformation of larvae into the second and third stages, within the human nose, is even more uncommon. To the best of our knowledge, we report the first Swedish case, and the third case world-wide, of Oestrus ovis larval development beyond the first larval stage, within an immunocompetent, healthy human.

Maggots reveal a case of antemortal insect infestation

Insects on corpses can give a wide range of information in forensic investigations. The most common application is calculating when insects oviposited on a dead person to give an estimation of the postmortem interval [1]. Since the infestation of a dead body may be delayed by certain circumstances such as indoor locations [2] or wrapping [3], it is more accurate to talk about the colonization time. Insects, being restricted to a certain area, can give further hints to the investigators such as if a body has been moved to a different location after death; also, body parts of insects can link a suspect to a crime scene [4]. Another application is the detection of toxic substances in insects feeding from dead persons' tissues [5]. There have been several studies done according to the biology of these animals' living associated with corpses as well as their application in legal investigations in the last years [6–12]. Many necrophagous flies are attracted by the odor of decomposition [13], but for some, other odors such as those from urine, feces, and the associated bacterial fauna are quite attractive and stimulate oviposition [14, 15]. The infestation of the living by dipterous fly larvae is known as myiasis. Wounds or anogenital regions are often found being fed by maggots in cases of neglect in humans or animals [16–19]. In certain cases, the chronologically nonmatching infestation of the anogenital area and favorable sites for oviposition of flies being attracted by the dead, such as the face, can give both the information of how long somebody has been neglected as well as how long a person has been dead [14, 15, 20]. Flies of the genus Lucilia belong to one of the first and most abundant summer species on corpses in Europe [21] and play an important role as facultative parasite causing myiasis [22]. It has to be emphasized that blowfly maggots will mostly feed from necrotic tissues [23] and will seldom eat the fresh and healthy skin or organs in humans or animals which has been reported for other fly species such as those from the family Oestridae under mostly tropical circumstances [24]. This unique property of fly maggots is commonly used in the maggot debridement therapy for treating nonhealing wounds [25]. Sterile fly larvae are applied to such resulting in a cleaning, disinfection, and increased healing-rate of the damaged tissue. The green bottle fly Lucilia sericata is the usual species used in this form of wound management [26]. The following case of an elderly dead woman reports the possibility to distinguish between maggot infestation before and after death, helping to reconstruct the formerly unknown circumstances.

Erratum to: Isolation of novel microsatellites for the howler monkey bot fly Cuterebra baeri (Diptera: Cuterebrinae)

Erratum to: Isolation of novel microsatellites for the howler monkey bot fly Cuterebra baeri (Diptera: Cuterebrinae)

Case Study - Deep Cutaneous Mass Excision Reveals an Unusual Finding

Case presentation of a 62-year-old male who presented to the emergency department complaining of a mass in his right hand which began 14 days prior to evaluation. The mass was located in the proximity of the multiple neurovascular structures; therefore, surgical excision in the operating room was required. The patient’s pathological findings revealed a thick-walled, smooth surfaced cyst consistent with a bot fly larva (Dermatobia hominis) enclosed in an exoskeleton casing, rendering the diagnosis furuncular myiasis. Because areas of cutaneous myiasis are frequently misdiagnosed as pyogenic infection, it is important that the clinician maintains bot fly larvae in their differential diagnosis for a boil-type lesion in a patient that has visited the American tropics. It is imperative that providers consider surgical consultation in cases of suspected cutaneous myiasis due to the likelihood of complex anatomical structural involvement or unforeseen difficulty in removal when the larva is located subdermally with fascial encasement.