Bot Fly Larvae Research Articles

Nasal myiasis in a cat caused by larvae of the nasal bot fly,Oestrus ovis

An 8-year-old desexed male Burmese cat, which lived on a sheep-grazing property in central New South Wales, Australia, was presented following the sudden onset of dyspnoea, moist coughing and violent sneezing. The respiratory distress started several hours after the cat had made an outdoor excursion. Anterior rhinoscopy demonstrated small, white objects moving across oedematous and moderately inflamed nasal mucosa. These were retrieved via a series of vigorous nasal flushes and subsequently identified as larvae of the nasal bot fly, Oestrus ovis. The cat was treated with ivermectin followed by selamectin 7 days later. It went on to make a complete recovery over 2-3 weeks.

Effect of Bot Fly Parasitism on Vertical Habitat use byPeromyscus leucopus

Peromyscus leucopus (White-footed Mouse) use the 3-dimensional space of their habitat. We studied whether Cuterebra fontinella (Bot Fly) larvae affected rate of capture in traps set above ground compared to traps set on the ground in deciduous forests in Ohio and Georgia. Rates of infestation were nearly three-fold greater in Ohio than in Georgia. Infested animals were captured equally in traps on the ground and in traps 1.5 m above ground in Ohio, but were captured less frequently in traps on the ground than in traps 1.5 m above ground in Georgia. Sex of animals did not affect these results. Infested animals were not captured in traps 4.5 m above the ground in Georgia, suggesting a possible limit to use of vertical habitat space by infested mice.

Implantation of Human Bot Fly Larvae in Host Skin

Adult males of Mus musculus each infested with four first-instar (L1) larvae of Dermatobia hominis (Linneaus, Jr.) were used as donors of larvae to other mice (recipients). Larvae at four (L1), six (early L2), 12 (L2), or 20 (L3) days postinfestation (dpi), were implanted into the skin of each recipient. Only two of 38 mice (5.3%) were refractory to implants and three died after implantation. Developmental times (pre- plus postimplantation) of implanted larvae were of similar duration to those in larvae that completed their development in the original mice. The L3 that emerged from implanted hosts developed to pupae and fertile adult specimens, whose L1 descendants were used to maintain the D. hominis life cycle in our laboratory. The model described here has several potential applications, including studies of the host relationship with specific instars and the development of management and control measures to combat this Neotropical myiasis.

Implantation of Human Bot Fly Larvae in Host Skin

Implantation of Human Bot Fly Larvae in Host Skin

Energetic cost of bot fly parasitism in free-ranging eastern chipmunks

The energy and nutrient demands of parasites on their hosts are frequently invoked as an explanation for negative impacts of parasitism on host survival and reproductive success. Although cuterebrid bot flies are among the physically largest and most-studied insect parasites of mammals, the only study conducted on metabolic consequences of bot fly parasitism revealed a surprisingly small effect of bot flies on host metabolism. Here we test the prediction that bot fly parasitism increases the resting metabolic rate (RMR) of free-ranging eastern chipmunks (Tamias striatus), particularly in juveniles who have not previously encountered parasites and have to allocate energy to growth. We found no effect of bot fly parasitism on adults. In juveniles, however, we found that RMR strongly increased with the number of bot fly larvae hosted. For a subset of 12 juveniles during a year where parasite prevalence was particularly high, we also compared the RMR before versus during the peak of bot fly prevalence, allowing each individual to act as its own control. Each bot fly larva resulted in a approximately 7.6% increase in the RMR of its host while reducing juvenile growth rates. Finally, bot fly parasitism at the juvenile stage was positively correlated with adult stage RMR, suggesting persistent effects of bot flies on RMR. This study is the first to show an important effect of bot fly parasitism on the metabolism and growth of a wild mammal. Our work highlights the importance of studying cost of parasitism over multiple years in natural settings, as negative effects on hosts are more likely to emerge in periods of high energetic demand (e.g. growing juveniles) and/or in harsh environmental conditions (e.g. low food availability).

An unusual cause of pre-auricular swelling

To present an interesting cause of pre-auricular swelling. We report the case of a 39-year-old woman who presented to the ENT department as an emergency with swelling in the left pre-auricular region. The patient had recently travelled to Central America, where the botfly is endemic. On examination, there was a raised, indurated area with a central orifice. A botfly larva was suspected. The larva was suffocated with paraffin paste, allowing removal without remnants being retained. Suffocation of botfly larvae is favoured to surgical removal, due to the possibility of larval remnants being retained and acting as a nidus for infection. The increasing frequency of exotic travel means doctors need to be more aware of tropical medicine.

Oestrus ovis causing human ocular myiasis: from countryside to town centre

Oestrosis caused by larvae of the sheep nasal botfly, Oestrus ovis (Diptera, Oestridae), is a zoonotic nasal myiasis affecting small ruminants (mainly sheep and goats) across the world, particularly in African and European Mediterranean countries. Reports of human oestrosis generally refer to people who have been closely associated with sheep and goat husbandry such as shepherds and farmers. Different clinical forms of human oestrosis are known, including external ophthalmitis, pharyngeal or laryngeal myiasis, nasal or auricular forms, with the possibility of combined clinical presentations. Reports of human infection by O. ovis have been increasing over the last few years and, recently, the first case of human oestrosis has been detected in a farmer living in the Canary Islands. Here we report the first confirmed case of human ocular myiasis by O. ovis, which has occurred in an urban environment.

Gastro-intestinal parasites in yearlings of wild Polish primitive horses from the Popielno Forest Reserve, Poland

Abstract To evaluate the gastro-intestinal parasite fauna of the wild Polish primitive horses (Equus caballus gmelini Ant., forma silvatica Vet.), 11 yearlings captured in the Reserve according to the control rules of population dynamics were diagnostically dewormed with abamectin+praziquantel. Expelled parasites were collected from the faeces 24, 36 and 48 hours after treatment. Among a total of 4456 specimens (a mean 405.1 per horse) 27 nematode species, one cestode and one species of botfly larvae were recovered. Strongylids were 100 % prevalent and represented by 24 species (2 large strongylid and 22 cyathostome species). Five cyathostome species (Cylicodontophorus bicoronatus, C. insigne, Poteriostomum imparidentatum, Parapoteriostomum mettami and Gyalocephalus capitatus) were recorded for the first time in Polish primitive horses, whereas two species (Cyathostomum montgomeryi and Cylicostephanus bidentatus) were found for the first time in the horse in Poland. Oxyuris equi was found in 100 % and Parascaris equorum in 63.6 % of yearlings surveyed. Tapeworms (Anoplocephala perfoliata) were revealed in 72.7 %, while Gasterophilus intestinalis instars in 90.9 % of horses. At least three parasite species were highly prevalent (i.e. S. vulgaris, A. perfoliata and G. intestinalis), which might be a reason of serious abdominal disorders in Polish horses living freely in the reserve.

Recognition and Management of Common Ectoparasitic Diseases in Travelers

This review article summarizes the ectoparasitic diseases likely to be seen by a Western dermatologist. The article aims to cover both endemic diseases and those likely to present in the returning traveler. Tungiasis is due to the gravid sand flea (Tunga penetrans) embedding into the stratum corneum of a human host. As the flea is a ground dweller, lesions are usually present on the feet and are classically periungual. The sand flea is eventually shed spontaneously but to reduce the infection risk, early surgical removal is recommended. Infestation by the Diptera species of fly causes myiasis, which may be primary, secondary, or accidental. The botfly (Dermatobia hominis) is one of the causes of primary myiasis covered in this article. Traditionally, botfly larvae are forced to partially emerge by occluding the breathing apparatus, following which manual extraction can occur. Alternatively, the larvae can be surgically removed. The common bed bug (Cimex lectularius) has experienced a resurgence over the past 10 years. Bites are typically arranged in clusters or a linear fashion and vary from urticated wheals to hemorrhagic blisters. Treatment is symptomatic with antihistamines and topical corticosteroids. In addition, bed bugs need to be eradicated from furniture and soft furnishings. Ticks are part of the Arachnid class of joint-legged animals and can transmit a variety of infections. This article briefly discusses Mediterranean spotted fever, Rocky Mountain spotted fever, and Lyme disease as well as describing tick avoidance measures. Scabies (Sarcoptes scabiei var hominis) is highly contagious and widely distributed around the world. It is common in the returning traveler and can require a high index of suspicion to diagnose. The treatment of choice in the US, UK, and Australia is permethrin 5% dermal cream, applied on two occasions, 1 week apart.

External Ophthalmomyiasis Caused by Oestrus ovis: A Rare Case Report from India

Myiasis of different organs has been reported off and on from various regions in the world. We report a human case of external ophthalmomyiasis caused by the larvae of a sheep nasal botfly, Oestrus ovis, for the first time from Meerut city in Western Uttar Pradesh, India. A 25-year-old farmer presented with severe symptoms of conjunctivitis. The larvae, 3 in number, were observed in the bulbar conjunctiva, and following removal the symptoms of eye inflammation improved within a few hours.

Effects of bot fly, Cuterebra fontinella, parasitism on male aggression and female choice in Peromyscus leucopus

Parasites can often impose a cost on their hosts by interfering with traits affected by sexual selection. We studied the effects of the bot fly, a common parasite of the white-footed mouse, Peromyscus leucopus , on host social behaviour using field-based experiments. Assuming parasite-induced costs on host behaviour, we expected that males uninfested with bot fly larvae would be more aggressive than infested males, and that reproductively active females would show a preference for uninfested males over infested males. Uninfested males were not more aggressive than infested males, based on two measures of aggression (principal component scores and number of aggressive behaviours). Contrary to our expectations, our results suggested that infested males may be more aggressive than uninfested males, but this result was based on the analysis of both aggressive and submissive behaviours. In addition, females spent more time with infested males. Thus, infestation may increase body size which could alter the outcome of female choice. Additional experimentation is necessary to tease apart the effects of increased body size and infestation on female choice.

Proteolytic activity in salivary gland products of sheep bot fly ( Oestrus ovis) larvae

This study identified and characterized hydrolytic enzymes in salivary gland products of Oestrus ovis larvae. Third instars were collected from the heads of slaughtered goats. Salivary glands were extracted, their products obtained by centrifugation and the enzymatic profile determined. Optimum pH, temperature of maximum proteolytic activity, thermal stability, and resistance of salivary gland products were determined on collagen and subclasses of proteases were identified using protease inhibitors. Zymograms were used to determine the molecular weight of proteases. Antigenic protein bands were revealed by immunoblotting using sera obtained from experimentally infested goats. Seven positive enzymatic activities were detected in salivary gland products: acid phosphatase, naphthol-AS-BI-phosphohydrolase, esterase (C4), esterase lipase (C8), leucine arylamidase, α-glucosidase and N-acetyl-β-glucosaminidase. Optimum pH for proteolytic activity was 8.0; proteolytic activity increased with temperature (10–50 °C) then drastically decreased at 60 °C. Proteases in O. ovis salivary gland products belong to the serine subclass. In Zymograms, bands of proteolytic activity were detected in the 20–63 kDa range; the immunoblot showed three antigenic bands, one of them related to a protease band (63 kDa). Serine proteases in O. ovis salivary gland products are most likely involved in larval nutrition and host immuno-modulation.

Observations of daytime births in two groups of red‐handed howlers (Alouatta belzebul) on an Island in the tucuruí reservoir in Eastern Brazilian Amazonia

Births were observed in two free-ranging groups of red-handed howlers (Alouatta belzebul) in eastern Brazilian Amazonia. Both events occurred in the early afternoon, and were relatively rapid and discrete. No other group members approached the females during parturition, nor attempted to interfere with the neonate in any way. Only one of the mothers ingested the placenta. This same female carried the neonate ventrally during the first month of life and then it was carried dorsally. The other infant was carried by its mother in a dorsal position from birth onward. Both infants survived their first month, but subsequently disappeared, in the second and fourth months of life. The precise causes of their death are unknown. In one case, we speculate that the infant's death was due to infestation by botfly larvae.

Stress and parasitism of white-footed mice (Peromyscus leucopus) in dry and floodplain environments

We hypothesized that flooding represents an environmental stressor that might affect the corticosterone levels, parasite prevalence, and life history of small mammals living in floodplain environments. We compared populations of white-footed mice ( Peromyscus leucopus (Rafinesque, 1818)) on floodplains and dry areas. We found more males on floodplains (p = 0.008) and more females on dry areas (p = 0.005). There were no differences in mass (p > 0.05) or intestinal parasite prevalence (p = 0.665) between dry and floodplain habitats, but bot fly larvae were significantly more prevalent in males living on floodplains (p = 0.043). Floodplain animals had significantly higher levels of corticosterone than dry-area animals in fall, and lower levels in summer (F[1,20] = 4.483, p = 0.047). In addition, we found that animals with intestinal parasites had higher levels of corticosterone than those that were without parasites (p = 0.014) or that harbored bot fly larvae (p = 0.001). Floodplains seem to be harsher environments than dry areas, but this may be a result of differences in habitat rather than a direct result of flooding.

Low reproductive success of Campo Suiriri (Suiriri affinis) and Chapada Flycatcher (S. islerorum) in the central Brazilian Cerrado

We investigated the reproductive success of Campo Suiriri (Suiriri affinis) and Chapada Flycatcher (S. islerorum) in the Estação Ecológica de Águas Emendadas, Central Brazil. Between June and December 2003, we monitored 25 nests of Campo Suiriri and 20 nests of Chapada Flycatcher. The simple percentage of successful nests was 32% for Campo Suiriri and 10% for Chapada Flycatcher, whereas the reproductive success calculated by the Mayfield method was 19% for Campo Suiriri and 14% for Chapada Flycatcher. The estimated values of daily survivorship rate (DSR) for Campo Suiriri are as follows: egg period 0.971 and nestling period 0.944. For Chapada Flycatcher the figures were 0.964 and 0.930, respectively. No differences in DSRs between species or periods were statistically significant. All nest losses of Campo Suiriri were due to predation, while for Chapada Flycatcher predation accounted for 78% of nest losses and the remaining 22% was due to parasitism by botfly larvae (Philornis sp.). The low reproductive success of Chapada Flycatcher is close to the lowest values recorded for Neotropical birds and might be a threat to this species and an important variable in the determination of its conservation status.

Parasites of domestic and wild animals in South Africa. XLVI. Oestrid fly larvae of sheep, goats, springbok and black wildebeest in the Eastern Cape Province

Merino sheep in Thornveld, Dorper sheep and Angora goats in inland Valley Bushveld, Angora goats and Boer goats in Valley Bushveld on the coastal plateau, and springbok, Antidorcas marsupialis, and black wildebeest, Connochaetes gnou, in Karroid Mountainveld, all in the Eastern Cape Province, were examined for the larvae of nasal bot flies. The sheep and goats were infested with the larvae of Oestrus ovis, and Dorper sheep and Boer goats harboured more larvae than Angora goats on the same farms. Most infestation was present from November to May in Merino sheep in Thornveld, from February to June in Dorper sheep in inland Valley Bushveld, and from May to September in Angora and Boer goats in Valley Bushveld on the coastal plateau. These patterns of seasonality appeared to be regulated by the severity of the summer temperatures at the various localities. The springbok were infested with the larvae of Rhinoestrus antidorcitis, most of which seemed to mature from June to August. All larval sages of Oestrus variolosus and Gedoelstia hässleri were present in the black wildebeest, and large numbers of 1st instar larvae of G. hässleri appeared to accumulate on the dura of the wildebeest from June to August.

Human botfly infestation presenting as peri-auricular mass

To report a new cause of peri-auricular mass in children: cutaneous myiasis-botfly infestation. Case report. The human botfly (Dermatobia hominis) is found in the tropics of Central and South America. However, cases of infestation are uncommon in the United States. We present the case of a 5-year-old girl with cutaneous myiasis in order to expand the differential diagnosis for a peri-auricular mass in children. In our report, the parasite was initially identified as sparganum, but was later reclassified by the center for disease control and prevention (CDC) as a botfly larva. Parasitic infection should be considered with a newly noted head and neck mass, and cutaneous myiasis should be included in the differential diagnosis. Cutaneous myiasis has not been previously reported in the literature describing the peri-auricular region as the site of occurrence. Furthermore, when an unusual parasite is extracted from a lesion, it should be confirmed by an authority such as CDC for definitive diagnosis, so appropriate plan of care and follow up can be instituted.

Endoparasites of African Forest Elephants (Loxodonta africana cyclotis) from the Republic of Congo and Central African Republic

Fecal samples were collected from 6 African forest elephants, Loxodonta africana cyclotis, from the Nouabale-Ndoki National Park, Republic of Congo, and the Dzangha-Sangha National Park, Central African Republic. One of the elephants was found freshly dead from natural causes, and 12 species of intestinal parasites (2 bot fly larvae, 1 trematode, and 9 nematodes) were collected during a complete necropsy. In addition, fecal samples revealed the presence of a schistosome, Bivitellobilharzia sp., a tracheal nematode, Mammomonagamus sp., and a complex of intestinal strongylids and ciliates. The nematode genera Decrusia and Equinurbia are reported for the first time from African elephants, and the ciliate genus Latteuria is reported for the first time from wild elephants. The parasite fauna of the African elephant is discussed in the light of recent genetic evidence that the forest and savannah elephants may be separate species.

Report in Europe of nasal myiasis by Rhinoestrus spp. in horses and donkeys: seasonal patterns and taxonomical considerations

Two species of Rhinoestrus (i.e. Rhinoestrus purpureus (Brauer) and Rhinoestrus usbekistanicus Gan) cause nasal myiasis in horses, donkeys and zebras. In the past 15 years myiasis caused by R. purpureus has been reported in Egypt and by R. usbekistanicus in Senegal and Niger, both in horses and in donkeys. With the aim to investigate the presence of this myiasis in autochthonous horses and donkeys from southern Italy and to study the seasonal trend of larval infection, 212 native horses were necropsied in two slaughterhouses in the Apulia region (site A) from January to November 2003, and 120 native horses and two donkeys in one slaughterhouse in Sicily (site B) from January to October 2003. Thirteen of 212 and 5 of 120 horses examined from sites A and B, respectively, were infected by nasal bot fly larvae. Both donkeys examined were positive. Two hundred and thirteen larvae, representing all stages, were collected from the throat region, the turbinates and beyond the lamina cribrosa of the ethmoid bone, in the cerebral cavity. Third larval stages were retrieved from April to September with the highest mean burden in site A in May and in July in site B. The simultaneous presence all three larval stages at site B suggests the existence of two or more overlapping generations. Larvae were identified on the basis of peritreme structures and arrangement of the spines on the dorsal surface of the third segment. Some L3 collected from sites A and B presented morphological characteristics of both R. usbekistanicus and R. purpureus. The presence of mixed features on the L3 of Rhinoestrus collected from the same animals may be explained by the existence of a single species of Rhinoestrus presenting different morphotypes or of two species of Rhinoestrus which are both present in southern Italy since this area is midway between eastern and African countries where these two species have been reported.

Human botfly larva in a child’s scalp

The botfly is the name for several families of hairy flies the larvae of which live as parasites in the bodies of mammals. Reported are the presentation, diagnosis, and noninvasive therapy for a botfly larva in the scalp of a 14 year old.