Tropical myiasis: an unwanted holiday souvenir

The Botfly, A Tropical Menace: A Distinctive Myiasis Caused by Dermatobia hominis

Dermatobia hominis, also known as the human botfly, is native to tropical and subtropical Central and South America and seen in travelers from endemic to temperate regions including the United States and Europe. Cutaneous infestation botfly myiasis involves the development of D. hominis larvae in the skin and is common in tropical locations. The distinct appearance of a cutaneous D. hominis infestation facilitates early diagnosis and intervention where cases are common. However, the identification of D. hominis in temperate regions may prove challenging due to its rarity. D. hominis may be misdiagnosed as folliculitis, an epidermal cyst, or an embedded foreign object with secondary impetigo. One should have a heightened suspicion in someone returning from a vacation in an endemic area, such as Belize. Here we describe the presentation, differential diagnosis, and treatment and encourage enhanced preventative measures among tourists when visiting tropical and subtropical regions. Additionally, we propose a novel classification system for assessing the various stages of infestation and suggest that patients reporting travel to Latin America and experiencing pain disproportionate to an insect bite should lead physicians to consider myiasis caused by D. hominis.

Human myiasis cases originating and reported in africa for the last two decades (1998-2018): A review

The article reviews literature on myiasis in Africa and cases that originated in Africa over the last two decades (1998-2018). The relevant literature was obtained by using several databases (Science-Direct, JSTOR, Google Scholar, Ebscohost and PubMed). We searched for the following words or their combination myiasis, maggots, fly species responsible for myiasis found in Africa, and the different types of myiasis. References in several articles provided links to other relevant works. Only papers written in English were reviewed. In total, we reviewed 51 articles which covered a total of 849 myiasis cases. The review encompasses geographical distribution of the disease, dipteran species responsible, predisposing factors, sex of the patient, type of myiasis and treatment. Myiasis is found in most parts of the African continent, however only 18 articles reported myiasis cases in Africa during the period under review. The rest of the articles report cases from the rest of the world but acquired by travellers when visiting Africa. Cordylobia anthropophaga (Blanchard) was responsible for 93.28% of all the reported cases in this review. The low number of articles on human myiasis reported in Africa may be due to underreporting by physicians or most cases are not diagnosed. Therefore, the actual prevalence of myiasis in Africa is currently unknown.

Myiasis caused by Dermatobia hominis: countries with increased risk for travelers going to neotropic areas

Here, we review the human botfly (Dermatobia hominis), which belongs to a group of Diptera generically known as "myiasis-causing flies," characterized by the ability of their larvae to develop in animal flesh. In addition to its medical and economic importance, there is an academic interest in this botfly because of its peculiar biology, particularly because a phoretic diptera is needed to complete the life cycle. The larvae penetrate the host's skin, causing furuncle-like lesions that are pruritic, painful, and resemble subcutaneous nodules, producing irreversible perforations in the skin. Although D. hominis is distributed from Mexico to Argentina, a review performed by our working group from 1999 to 2015 determined that the countries with the highest infection rates in travelers are Belize, Bolivia, and Brazil. Interestingly, infected men show a higher variation in the distribution of the lesions than in women. Many treatment schemes have been suggested, including the application of highly dense liquids to the lesion to cause anoxia in the D. hominis larvae. We showed, for the first time, a Bayesian inference between D. hominis and other myiasis-causing flies. The flies grouped into two main clusters according to their capacity to produce facultative and obligatory myiasis, and D. hominis was phylogenetically close to Cuterebra spp.

Exotic human myiasis

Human myiasis may be caused by several species of dipterous larvae. It is widespread in the tropics and subtropics particularly in Africa and the Americas and can occur in other parts of the world although less frequently. Larval infestation mostly affects the skin but can also involve wounds, bones, intestines and body cavities. Diagnosis is mainly clinical. The rule of treatment is to remove the larvae and treat any associated infection. Frequent international travel, immigration and rising global trade increase the likelihood of imported infestations. It is therefore vital that physicians in non-endemic areas are aware of clinical symptoms, exposure and presentation of this condition, as early recognition would prevent any costly, inappropriate treatments or complications. We report a case of imported human myiasis and present a literature review of human myiasis.

Imported disease in emergency departments: an undiscovered country?

BACKGROUND

The incidence of imported disease within the emergency department (ED) is not known, but a significant number of patients present to medical services after return from traveling. Unless practitioners in ED are aware of the potential for nonendemic disease in the population of patients they attend, there is a possibility that imported diseases will not be diagnosed in the acute setting.

METHOD

A questionnaire was sent to all medical practitioners involved in assessing patients presenting to the EDs of hospitals. This questionnaire consisted of five clinical scenarios describing acute presentations of imported diseases but without a travel history included. Responses were requested to ascertain whether practitioners would elucidate the travel history and consequently establish the correct diagnosis.

RESULTS

A response rate of 96% was achieved. When presented with a clinical scenario suggesting imported disease, travel history is only elicited in 16% of cases by the acute care practitioners. A correct diagnosis was given in 22% of responses. Interestingly, there was generally no significant correlation between eliciting a travel history and establishing the correct diagnosis.

CONCLUSIONS

When presented with a clinical scenario that describes an imported disease, medical practitioners in EDs do not routinely establish a travel history or consider the diagnosis of imported disease. There may be a high potential for imported disease to be missed in the ED.