Sheep blowfly strike risk and management in Great Britain: a survey of current practice

Abstract

The methods used for the control of sheep blowfly strike (ovine cutaneous myiasis) and the farm management factors associated with strike prevalence were examined using data from questionnaire survey returns provided by 966 sheep farmers in Great Britain, based on the period between March 2003 and February 2004. Overall, 91% of participants treated prophylactically with insecticides against blowfly strike; 39% treated twice and 11% treated more than three times in the year. Insect growth regulators (IGRs) were the most commonly chosen product (40%), especially the IGR cyromazine. Only 12% of farmers opted to dip their sheep in organophosphate insecticide against fly strike and 2% of farmers reported applying inappropriate products against strike to their sheep, such as ivermectin or 'drenches'. Farmers worming their ewes more often were 0.8 times less likely to report blowfly strike, but those who wormed their lambs more often were 1.2 times more likely to report strike. Pure-breed flocks were 0.7 times less likely to record an outbreak of blowfly strike than cross-breed flocks. Strike was less likely in ewe flocks grazed at higher altitude; however, this relationship with altitude was not seen in lambs. The results show that insecticides remain the primary tool used by almost all farmers to prevent strike and that the type of insecticides used and means of application have altered dramatically over the past 15 years. However, the prevalence of strike has remained almost unchanged over this period. Clearly careful attention to the type and timing of insecticide application, in association with a detailed understanding of the husbandry factors that predispose sheep to higher strike risk, is essential to allow the optimal management of strike problems.

Molecular characterization and expression pattern of an odorant receptor from the myiasis-causing blowfly, Lucilia sericata (Diptera: Calliphoridae)

“…Lucilia sericata (Meigen) (Diptera: Calliphoridae), more commonly known as the sheep blowfly, is the primary agent of ovine cutaneous myiasis (blowfly strike) in many European countries such as England, Netherlands and Germany, and parts of the southern hemisphere (Snoep et al 2002;Bisdorff and Wall 2008;Mehlhorn et al 2010). The feeding activity of larvae at the skin surface can lead rapidly to the development of cutaneous lesions, further oviposition, debilitation, and the subsequent death of the infested animal, unless treated (Harvey et al 2010).…”

Sheep blowfly strike: the cost of control in relation to risk

“…The model was used to estimate the effects of blowfly strike when using different treatment strategies (Table 1). These strategies were based on typical patterns of management used by UK farmers (French et al, 1994;Bisdorff et al, 2008). For each management strategy, the model used the expected duration of protection from strike based on the label claim of the product in question to reduce the risk to zero, and added the costs of treatment, reduced productivity, labour and deaths.…”

“…A range of insecticides are available to control blowfly strike and can be used both prophylactically and reactively (Bates, 2004;Bisdorff & Wall, 2008). These include the organophosphate diazinon, the pyrethroids high cis-cypermethrin, alphacypermethrin and deltamethrin and insect growth regulators (IGRs) such as cyromazine and dicyclanil (Wall and Lovatt, 2015).…”

“…Although the majority of farmers use IGRs for strike control, the lower cost of pyrethroids results in continued popularity (35% of farmers in 2003. Bisdorff & Wall, 2008) while others continue to summer-dip with organophosphate (12% of farmers in 2003; Bisdorff & Wall, 2008) although parasiticide usage patterns may vary substantially with region (Chivers et al, 2018).…”

Genome sequence of Phormia regina Meigen (Diptera: Calliphoridae): implications for medical, veterinary and forensic research

“…Within Diptera, the family Calliphoridae, commonly known as blow flies, comprises ~1500 species [6, 7], and contributes 8 % of species diversity in calyptrate flies [8]. Calliphorids are ubiquitous, distributed world-wide, and are important in the medical [9–12], veterinary/agricultural [13–16] and forensic fields [17, 18]. For example, blow flies are responsible for the transmission of human disease [19–22].…”