Field trial of the efficacy of dicyclanil for the prevention of wohlfahrtiosis of sheep

Long Time No Hear, Magnificent Wohlfahrtia! Morphological and Molecular Evidence of Almost Forgotten Flesh Fly in Serbia and Western Balkans

The "beautiful viviparous fly", Wohlfahrtia magnifica, may have a magnificent appearance due to its striking morphology; however, it is a potentially deadly agent of obligate traumatic myiasis in humans and animals, with a serious impact on welfare and economics. The fly is found across the Palearctic realm, including the Western Balkan region, with reports from former Yugoslavian countries from the first half of the 20th century. In this paper, a recent case of wohlfahrtiosis recorded in Northern Serbia is evidenced using morphological and molecular techniques. Larvae were collected from two adult sheep with severe hoof myiasis and two young sheep with genital and interdigital myiasis. Morphological identification was performed for adults bred from the infested vulva and third-stage larvae (L3) collected from the hoof wounds, supported with barcoding sequences of the COI gene obtained from larval pairs from the hoof wounds of older and the genitalia of younger sheep. W. magnifica was identified according to the appearance of male fly terminalia and the morphology of L3, which was confirmed after the comparison of representative sequences of the COI gene (deposited in GenBank™ under accession numbers MT027108-MT027114) to those available in GenBank™. This finding represents the first reported case of wohlfahrtiosis in the Western Balkans in 80 years, highlighting the need to re-inform relevant stakeholders to achieve adequate disease control.

A retrospective and geographical epidemiological survey of traumatic myiasis in southern Italy

A survey on the prevalence and geographical distribution of traumatic myiasis in sheep, and the risk factors for the disease, was carried out in a region of southern Italy. A total of 138 sheep flocks were selected and visited to acquire data on the presence or absence of traumatic myiasis using both a questionnaire for retrospective analysis and animal inspection. Prevalences registered at the farm and animal levels, respectively, were 8.7% and 6.3% in 2010, and 5.8% and 5.0% in 2011. Records of the occurrence of the parasitic disease in this region are recent: a statistically significant (P < 0.01) progressive increase in the number of farms affected (from 0.7% to 8.7%) has been registered since 2007. Wohlfahrtiosis was found in 11 of 95 (11.6%) geographical units sampled and three significant (P < 0.05) clusters of spatial farm aggregation were identified in the southern part of the study area. A total of 158 presently uninfested farms were considered to be at high risk for transmission as a result of their proximity to infested farms. The spreading of Wohlfahrtia magnifica (Diptera: Sarcophagidae) in southern regions of Italy represents a warning that the risk for infestation may become more significant in other Italian regions, as well as other European countries.

Simultaneous determination of cyromazine and dicyclanil in animal edible tissues using UPLC-MS/MS

Cyromazine and dicyclanil are both used as insect growth regulators. This paper describes an easy and innovative simultaneous extraction method for residues of cyromazine and dicyclanil in food of animal origin, and a confirmation procedure using UHPLC-MS/MS. The sample was extracted, deproteinised by 1% trichloracetic acid in water-acetonitrile, followed by selective defatting using hexane based on the degree of matrix complexity; cleaned-up on an mixed-mode cation exchange (MCX) cartridge; and quantified by using matrix-matched calibration. The mean recoveries were all between 62.0% and 99.2%, and the RSDs were all below 9.94%. The present method was rapid, sensitive and reliable, which was applied to the quantitative analysis of these residues in animal tissues.

Fleshflies in the flesh: epidemiology, population genetics and control of outbreaks of traumatic myiasis in the Mediterranean Basin

Although the damaging effects on healthy tissues of its developing larvae were first described in 1770, the fleshfly Wohlfahrtia magnifica remains a serious pest for the livestock industry. Wohlfahrtiosis, the severe myiasis caused by this fly, is a grave problem in terms of both the animal welfare and economic loss. This review highlights important aspects of the biology, pest status, epidemiology, population genetic structure, economics and control of W. magnifica and wohlfahrtiosis, with an emphasis on recent outbreaks in Greece and Morocco and fly population dynamics in the Mediterranean Basin. Potential areas for future studies on genetics, host tolerance, in vitro rearing, field behaviour and range expansion of the species are also discussed.

Molecular genetic analysis of populations of Wohlfahrt's wound myiasis fly, Wohlfahrtia magnifica, in outbreak populations from Greece and Morocco

Wohlfahrt's wound myiasis fly, Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae), is the most important cause of traumatic myiasis in the southern Palaearctic region. Larval stages are obligate parasites and the wounds caused by infestations are very similar to those caused by Old and New World screwworm flies. During the last decade, W. magnifica appears to have expanded its range to parts of northern and central Morocco, and to Crete, Greece. Specimens of W. magnifica were collected in Morocco and Crete either as larvae (preserved in 80% ethanol) or as adults (dry-pinned). Comparison specimens were collected in Spain, Hungary and mainland Greece. A DNA fragment containing the 3' 715 base pairs of the mitochondrial cytochrome b gene was amplified by polymerase chain reaction from each of 132 larvae or adults of W. magnifica and the amplicons were directly sequenced and analysed phylogeographically. Twelve cytochrome b haplotypes were detected. All haplotypes from Morocco belonged to a lineage that included specimens from the Iberian peninsula, and restricted mixing of central and northern populations in Morocco was demonstrated. Cytochrome b haplotyping combined with an analysis of larval size provided clear evidence of multiple infestations of hosts in all geographical areas, with one quarter of wounds containing larvae from two to at least four females. More than 80% of specimens from Crete contained a haplotype predominating in mainland Greece and Hungary. Our survey indicated that wohlfahrtiosis was more widespread in northern and central Morocco than previously recorded by government veterinarians. However, the prevalence of wohlfahrtiosis was low (< 1%). The high genetic diversity of Moroccan populations is consistent with longterm endemicity, rather than recent introduction. Crete showed a higher prevalence of wohlfahrtiosis (< or = 15%) and less genetic diversity of W. magnifica, which is consistent with a recent introduction. The western and eastern Mediterranean lineages may have been isolated in different Pleistocene ice-age refugia, from which there has been limited post-glacial dispersal.

Wohlfahrtiosis in sheep and the role of dicyclanil in its prevention

Wohlfahrtia magnifica is the main agent of traumatic myiasis in the southern Palaearctic zone. It was recorded in outbreak situations in Crete, Greece, for the first time in 1999, causing widespread production losses and considerable concern in the livestock sectors. Most commonly applied curative insecticides, organophosphates and pyrethroids, can kill larvae of W. magnifica, but they do not provide long-term protection from infestation or re-infestation, which would facilitate wound healing. The objective of the present work was to study the seasonal dynamics of sheep wohlfahrtiosis in Crete and to determine the prophylactic efficacy of dicyclanil, an insect growth regulator, against natural infestations by larvae of W. magnifica. Six sheep flocks were studied, three from a semi-intensive husbandry system and three from an extensive husbandry system. Two flocks were kept as untreated controls and also were used to study the disease dynamics. Dicyclanil was strategically applied just to males and young non-milking females in four treatment flocks; milking females in these flocks were not treated. The untreated flocks demonstrated seasonal patterns in case numbers that were associated with changes in climate and husbandry activities, especially reproduction and shearing. Cases were most common on the genitalia (60%) and a greater proportion of males than females were infested. The prophylactic efficacy of dicyclanil in males was up to 91.3% over the entire trial period. Hence the incidence in treated males at 22 weeks, when final infestations were recorded, was 5-10% compared to 45-55% in untreated controls. Moreover, the application of dicyclanil to a limited number of animals per flock (males and non-milking females=c. 15-20% of the flock) significantly reduced the incidence of wohlfahrtiosis even in the untreated animals. Hence, final overall incidences in the treated flocks ranged from 4.5 to 5.5% compared to 13.3-13.4% in the control flocks.