Evaluation of larval density Cochliomyia macellaria F. (Diptera: Calliphoridae) for therapeutic use in the recovery of tegumentar injuries.

Larval therapy (LT) is the application of carrion flies (Diptera) sterile larvae on chronic or infected wounds to promote or accelerate the healing process. High cost and the development of resistance by certain groups of pathogenic bacteria to these drugs encouraged the resurgence of LT, currently used in approximately 20 countries and more recently in Brazil. This study evaluated the behavior and larval density of Cochliomyia macellaria F. (Calliphoridae), one of the most appropriate species for debridement of injuries with necrotic tissue. Tegumentar lesions were induced in Wistar rats by subcutaneously application of 0.2 ml of a 1:4 hydrochloric acid and sterile distilled water in the dorsal region. Five experimental groups were set up: (LT 5) treatment with 5 larvae/cm(2); (LT 15) 15 larvae/cm(2); (LT 25) 25 larvae/cm(2); (DEB) mechanical debridement, and (NUL) animals that did not receive any treatment. In the LT groups, larvae used were sterilized with sodium hypochlorite (NaClO) and maintained for 12 h in the lesions. The healing process was assessed qualitatively (macroscopically and microscopically) and quantitatively (time interval to complete healing). It was observed that the immature fed only on necrotic tissue, thus C. macellaria is an excellent candidate for use in LT. There was no significant difference in healing time between experimental groups. However, it was observed that in LT 25, there was greater vascularization in tissues when compared to the other treatments. The mechanisms involved in this process are unknown, but it is evident that the larvae have an important role in modulating the host immune response. It is essential that future applications of larval therapy consider using a higher density of larvae (minimum of 25 larvae/cm(2)) than is currently recommended.

Histological patterns in healing chronic wounds using Cochliomyia macellaria (Diptera: Calliphoridae) larvae and other therapeutic measures.

The healing process occurs due to the interaction of cellular, molecular, and biochemical events. Regarding lesions difficult to heal, especially in immunocompromised patients, monitoring and intervention to promote healing is a constant focus of research. Another aggravating factor is the increase in the number of reported cases of microbial resistance, indicating that various dressings and drugs have been increasingly inefficient. Larval therapy (LT) involves the application of sterile fly larvae on chronic and/or infected wounds, and it is an area emerging as an alternative therapy. Before the 1940s, the LT was widely used, but fell into disuse after the appearance of antibiotics. High cost and the development of resistance by certain groups of pathogenic bacteria to these drugs encouraged the resurgence of LT, currently used in approximately 20 countries and more recently in Brazil. However, many mechanisms of action of the larvae in this system remain poorly understood. Thus, the aim of the study was to investigate histopathological findings and to evaluate possible mechanisms of action of dipteran larvae during tissue repair. Lesions were induced in 24 male Wistar rats, to evaluate the effect of the type of treatment applied. The animals were divided into four groups: larval therapy (LT), LT associated with foam dressing with silver release (LTSIL), mechanical debridement and silver foam dressing (DEBSIL), and no treatment (CONT). Skin samples were collected for histopathological analysis. In LT, inflammatory response and angiogenesis were abundant; in LTSIL, inflammatory response with neutrophil infiltration was observed; in DEBSIL, scarce inflammatory response, small numbers of macrophages and lymphocytes, and bacterial colonization in depth; and in CONT, there was bacterial colonization in deeper tissues. The observed histological events show that the larvae had an important role in promoting the inflammatory response in the wound bed, drawing the essential immune cells for tissue reconstruction, and contributing to the inhibition of bacterial growth. However, more studies on the larval-host interactions are required for increasing the application of LT in the hospital routine.

Developmental rate of immatures of two fly species of forensic importance: Sarcophaga (Liopygia) ruficornis and Microcerella halli (Diptera: Sarcophagidae).

Since insect species are poikilothermic organisms, they generally exhibit different growth patterns depending on the temperature at which they develop. This factor is important in forensic entomology, especially for estimating postmortem interval (PMI) when it is based on the developmental time of the insects reared in decomposing bodies. This study aimed to estimate the rates of development, viability, and survival of immatures of Sarcophaga (Liopygia) ruficornis (Fabricius 1794) and Microcerella halli (Engel 1931) (Diptera: Sarcophagidae) reared in different temperatures: 10, 15, 20, 25, 30, and 35 ± 1 °C. Bovine raw ground meat was offered as food for all experimental groups, each consisting of four replicates, in the proportion of 2 g/larva. To measure the evolution of growth, ten specimens of each group were randomly chosen and weighed every 12 h, from initial feeding larva to pupae, and then discarded. Considering the records of weight gain, survival rates, and stability of growth rates, the range of optimum temperature for the development of S. (L.) ruficornis is between 20 and 35 °C, and that of M. halli is between 20 and 25 °C. For both species, the longest times of development were in the lowest temperatures. The survival rate at extreme temperatures (10 and 35 °C) was lower in both species. Biological data such as the ones obtained in this study are of great importance to achieve a more accurate estimate of the PMI.

Record of oral myiasis by Cochliomyia hominivorax (Diptera: Calliphoridae): case evidencing negligence in the treatment of incapable.

Cases of myiasis in man associated with preexisting lesions are quite common. However, in the forensic field, certain behavioral habits related to insects may be useful to ratify mistreatment. This is a register of a case of oral myiasis by Cochliomyia hominivorax (Diptera: Calliphoridae), an obligate parasite of warm-blooded animals, in a 95-year-old man with Alzheimer's and Parkinson's disease. The identification of immatures removed (n = 87) was based on their morphological characteristics. Considering the developmental time and length of the maggots, it was possible to estimate an infestation of at least 143 h. Undoubtedly, the poor state of health was one of the cofactors for the infestation; however, the long time of infestation observed denotes negligence in the conduct of patient care. In terms of prophylaxis, it would be recommended that individuals who need special care must have access to more comprehensive physical examinations and periodicals, as well as hygienic conditions should be meticulously observed. Additionally, the immatures causing myiasis after being removed must be stored and forwarded for analysis, since their identification can be crucial to determine the exact time and circumstances of an infestation, and consequently its pathogenesis. If we consider the aggressiveness of C. hominivorax, a fast and reliable diagnosis becomes even more important for an adequate treatment. Finally, it is expected that this study encourages the health care professionals to improve the treatment of incapable patients.