Identification of screwworms, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), with a monoclonal antibody-based enzyme-linked immunosorbent assay (MAb-ELISA)

First record of traumatic myiasis obtained from forest musk deer (Moschus berezovskii)

Myiasis is an infestation of maggots on living tissue in humans and animals all over the world. It is known to occur in wild animals, while no information is reported in forest musk deer (Moschus berezovskii). During our research on the conservation of forest musk deer, we found a new record of traumatic myiasis of an injured forest musk deer. The flies are likely Lucilia caesar (Linnaeus, 1758) according to the results of DNA barcoding technology. We report traumatic myiasis of forest musk deer for the first time, which expands the information on parasite and myiasis of forest musk deer and confirms the potential risk of traumatic myiasis of forest musk deer.

Review of Molecular Identification Techniques for Forensically Important Diptera

The medico-legal section of forensic entomology focuses on the analysis of insects associated with a corpse. Such insects are identified, and their life history characteristics are evaluated to provide information related to the corpse, such as postmortem interval and time of colonization. Forensically important insects are commonly identified using dichotomous keys, which rely on morphological characteristics. Morphological identifications can pose a challenge as local keys are not always available and can be difficult to use, especially when identifying juvenile stages. If a specimen is damaged, certain keys cannot be used for identification. In contrast, molecular identification can be a better instrument to identify forensically important insects, regardless of life stage or specimen completeness. Despite more than 20 yr since the first use of molecular data for the identification of forensic insects, there is little overlap in gene selection or phylogenetic methodology among studies, and this inconsistency reduces efficiency. Several methods such as genetic distance, reciprocal monophyly, or character-based methods have been implemented in forensic identification studies. It can be difficult to compare the results of studies that employ these different methods. Here we present a comprehensive review of the published results for the molecular identification of Diptera of forensic interest, with an emphasis on evaluating variation among studies in gene selection and phylogenetic methodology.

Sequence-characterized amplified regions that differentiate New World screwworms from other potential wound-inhabiting flies

New World screwworms, Cochliomyia hominivorax (Coquerel, 1858), were once devastating pests of warm-blooded animals in the United States before they were successfully eradicated using the sterile insect technique. Guarding against the introduction of screwworms to North America or any other screwworm-free area relies on rapid, reliable identification of suspected cases. In the current study, the DNA from excised markers generated by randomly amplified polymorphic DNA polymerase chain reaction was used as the basis to generate 2 species-specific sequence-characterized amplified region molecular markers. Resulting primer pairs, named CR92A1 and J1A2 (each with forward and reverse components), produced amplicons of 852 and 848 base pairs, respectively. The 2 primer pairs successfully discriminated between C. hominivorax, Cochliomyia macellaria (Fabricius, 1775), 8 other species of blowflies, 3 noncalliphorid dipterans, and 1 nondipteran outlier. These primers may become important tools for veterinary laboratories and the screwworm eradication and exclusion program for rapid identification or verification of suspicious larval samples in presumed outbreaks.

Amplified fragment length polymorphism used for inter- and intraspecific differentiation of screwworms (Diptera: Calliphoridae)

Morphologically, early immature stages of the economically important pest called screwworms, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), and non-pest secondary screwworms, Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae), are nearly indistinguishable. Correct identification is crucial to the ongoing eradication and exclusion program protecting the United States, Mexico and Central America from reinvasion of screwworms persistent in South America and the Caribbean. Amplified fragment length polymorphism (AFLP) polymerase chain reaction was used to differentiate populations of C. hominivorax and to discriminate them from C. macellaria. Ten primer pairs screened for interspecific discrimination of C. hominivorax from C. macellaria showed 52 discrete bands, allowing the two species to be readily distinguished; divergent branches on resulting dendrograms showed 100% bootstrap support. C. macellaria populations grouped at the 92% level; C. hominivorax populations grouped at the 68% level. Of the 52 bands, seven were monomorphic for both species, 22 were specific to C. macellaria, ten were present only in C. hominivorax and the remaining 13 bands differentiated C. hominivorax populations. Separate studies using ten strains of C. hominivorax showed a higher level of genetic similarity within than between populations. Analyses using 72 bands (19 monomorphic bands, 53 bands grouped all ten strains at the 58% similarity level) resolved seven mutant strains from Mexico (85% similarity level); all ten strains were resolved at the 72% similarity level. Diagnostic bands were identified for species and strain identification. We conclude that AFLP can be a valuable tool for studies of interspecific and intraspecific genetic variation in screwworm populations.

Screwworms

New World and Old World screwworms pose threats to the livestock industry in the United States and other countries. Diligence on the part of veterinarians, physicians, and their respective staffs is essential to protect the livestock industry.

Molecular approaches to the study of myiasis-causing larvae

Among arthropod diseases affecting animals, larval infections - myiases - of domestic and wild animals have been considered important since ancient times. Besides the significant economic losses to livestock worldwide, myiasis-causing larvae have attracted the attention of scientists because some parasitise humans and are of interest in forensic entomology. In the past two decades, the biology, epidemiology, immunology, immunodiagnosis and control methods of myiasis-causing larvae have been focused on and more recently the number of molecular studies have also begun to increase. The 'new technologies' (i.e. molecular biology) are being used to study taxonomy, phylogenesis, molecular identification, diagnosis (recombinant antigens) and vaccination strategies. In particular, more in depth molecular studies have now been performed on Sarcophagidae, Calliphoridae and flies of the Oestridae sister group. This review discusses the most topical issues and recent studies on myiasis-causing larvae using molecular approaches. In the first part, PCR-based techniques and the genes that have already been analysed, or are potentially useful for the molecular phylogenesis and identification of myiasis-causing larvae, are described. The second section deals with the more recent advances concerning taxonomy, phylogenetics, population studies, molecular identification, diagnosis and vaccination.