World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) second edition: guidelines for evaluating the efficacy of parasiticides for the treatment, prevention and control of flea and tick infestations on dogs and cats.

These second edition guidelines, updated from the 2007 version (Marchiondo et al., 2007), are intended to assist the planning and conduct of laboratory and clinical studies to assess the efficacy of ectoparasiticides applied to dogs or cats for the purpose of treating, preventing and controlling flea and tick infestations. Major revisions to this second edition include guidelines on the assessment of systemic flea and tick products, an update of the geographical distribution of the common fleas and ticks species on dogs and cats, determination of flea and tick efficacy based on geometric versus arithmetic means with respect to geographic regulatory agencies, modification of tick categorization in the assessment of efficacy, expanded guidelines on repellency and anti-feeding effects, enhanced practical field study guidance, and considerations on the ranges of flea and ticks for infestations in laboratory studies. The term ectoparasiticide includes insecticidal and acaricidal compounds, as well as insect growth regulators. The range of biological activities from animal treatment that are considered include: repellency and anti-feeding effects, knockdown, speed of kill, immediate and persistent lethal effects, and interference with egg fertility and subsequent development of off-host life cycle stages. Information is provided on the selection of animals, dose determination, dose confirmation and field studies, record keeping, interpretation of results and animal welfare. These guidelines are also intended to assist regulatory authorities involved in the approval and registration of new topical or systemic ectoparasiticides, and to facilitate the worldwide adoption of harmonized procedures.

The efficacy of a topically applied combination of cyphenothrin and pyriproxyfen against the southern African yellow dog tick, Haemaphysalis elliptica, and the cat flea, Ctenocephalides felis, on dogs.

The objective of this study was to determine the therapeutic and residual efficacy of a topically applied combination of cyphenothrin (40%) and pyriproxyfen (2%) against the tick Haemaphysalis elliptica and the flea Ctenocephalides felis on dogs. Twelve dogs were infested with 50 ticks 2 days before they were treated and with approximately 100 fleas 6 days before treatment and again 2 days before treatment and with 50 ticks and approximately 100 fleas at weekly intervals thereafter. They were ranked according to their flea counts and sex 5 days before treatment and randomly allocated to an untreated control group of 6 dogs and a treated group of 6 dogs. Ticks and fleas were collected from the dogs 48 h after treatment and 48 h after each infestation and live and dead ticks and live fleas were counted. The counts of ticks and fleas were transformed to geometric means, and efficacy was calculated by comparing these means. The product had a therapeutic efficacy of 83.1% against H. elliptica and 97.5% against C. felis 2 days after treatment. The residual period of protection during which efficacy was > or = 90% was 5 weeks for both H. elliptica and C. felis.

Efficacy of a novel formulation of metaflumizone plus amitraz for the treatment of sarcoptic mange in dogs.

A novel spot-on formulation containing metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated for efficacy against sarcoptic mange mites in naturally infested dogs. Sixteen dogs were allocated to two equal groups and were housed individually. Eight of the dogs were treated topically with metaflumizone plus amitraz at the proposed minimum dose rate (20mg/kg of each of metaflumizone and amitraz, at a dose volume of 0.133ml/kg) on Days 0 and 28. The other eight were treated with metaflumizone plus amitraz at the proposed minimum dose rate on Days 0, 14, 28 and 42. To enumerate Sarcoptes scabiei mites, skin scrapings were taken on each of Days 2, 14, 28, 42 and 56. Clinical signs of mange and the extent of sarcoptic lesions were evaluated on each dog when scrapings were made. Evaluation of the efficacy of the treatment was based on the absence of mites supported by the absence of clinical signs associated with canine sarcoptic mange. Treatment with metaflumizone plus amitraz at the minimum proposed dose rate at monthly (two treatments) or two-weekly (four treatments) intervals resulted in a rapid reduction of mites and improved clinical signs. The overall cure rates at Day 56, based on zero mite counts and/or resolution of clinical signs were 75% and 83% of dogs for the monthly and two-weekly regimens, respectively.

Efficacy of a novel formulation of metaflumizone plus amitraz for the treatment of demodectic mange in dogs.

A novel spot-on formulation containing metaflumizone plus amitraz (ProMeris/ProMeris Duo for Dogs, Fort Dodge Animal Health, Overland Park, KS) was evaluated for efficacy against demodectic mange mites in naturally infested dogs. Sixteen dogs were allocated to two equal groups and individually housed. Eight of the dogs were treated topically with metaflumizone plus amitraz at the proposed minimum dose rate (20mg/kg of each of metaflumizone and amitraz, 0.133ml/kg) on Days 0, 28, and 56. The other eight were treated with metaflumizone plus amitraz at the proposed minimum dose rate on Days 0, 14, 28, 42, 56, and 70. Mite numbers were estimated from skin scrapings taken on Days -3 to -1, 28, 56, and 84. Clinical signs of mange and the extent of demodectic lesions on each dog were evaluated when skin scrapings were conducted. Efficacy of the treatment was based on a reduction in mite numbers and an assessment of the clinical signs associated with canine demodectic mange. Treatment at monthly or two-weekly intervals for 3 months resulted in a rapid reduction in mite numbers (>94 and >99% for the monthly and two-weekly treatments, respectively) and an improvement in clinical signs. Success rates, based on zero mite counts in skin scrapings at Day 84 were 42.9 and 62.5% of dogs for the monthly and two-weekly regimens, respectively.

Birds as hosts of immature ixodid ticks in Free State Province, South Africa.

The objective of this study was to determine the species spectrum of ixodid ticks infesting birds in Free State Province, South Africa. To this end a large number of birds belonging to several species were examined for ticks and a total of 180 birds belonging to 39 species at 17 localities were infested, and ticks belonging to eight species were recovered. The immature stages of only two, namely Amblyomma marmoreum and Hyalomma marginatum rufipes, were sufficiently prevalent and numerous to safely assume that they regularly use birds as hosts. Helmeted guineafowls, Numida meleagris, were the most heavily infested and one harboured a total of 319 larvae and four nymphs. Amongst the other species an eastern clapper lark, Mirafra fasciolata, was infested with 69 larvae and a nymph, but no other bird harboured more than 40 ticks. The larvae and nymphs of H. m. rufipes were most numerous on birds from April to August.

The efficacy of an imidacloprid/moxidectin combination against naturally acquired Sarcoptes scabiei infestations on dogs.

The study was undertaken to evaluate and compare the efficacy of an imidacloprid (10% w/v)/moxidectin (2.5% w/v) combination (Advocate Bayer HealthCare, Animal Health) with that of selamectin for the treatment of Sarcoptes scabiei on dogs. Thirty naturally infested dogs, of which one was later withdrawn because of distemper, were allocated to two equal groups and individually housed. The dogs in each group were treated twice, four weeks apart, with either the combination product (0.1 mL/kg body weight) or with selamectin (0.05 mL/kg body weight) administered topically. Skin scrapings were made every 14 days over a period of 50 to 64 days after the first treatment to quantify mite numbers. Clinical signs and the extent of sarcoptic lesions were assessed on each dog when skin scrapings were made. Efficacy was based on the presence or absence of mites, supported by clinical signs associated with canine sarcoptic mange. From Day 22 and onwards no Sarcoptes mites were found in the skin scrapings of any of the treated dogs. Treatment with the imidacloprid/moxidectin formulation or with selamectin was highly effective against Sarcoptes scabiei and resulted in an almost complete resolution of clinical signs within 50 to 64 days after the initial treatment.

Small mammals as hosts of immature ixodid ticks.

Two hundred and twenty-five small mammals belonging to 16 species were examined for ticks in Free State, Mpumalanga and Limpopo Provinces, South Africa, and 18 ixodid tick species, of which two could only be identified to genus level, were recovered. Scrub hares, Lepus saxatilis, and Cape hares, Lepus capensis, harboured the largest number of tick species. In Free State Province Namaqua rock mice, Aethomys namaquensis, and four-striped grass mice, Rhabdomys pumilio, were good hosts of the immature stages of Haemaphysalis leachi and Rhipicephalus gertrudae, while in Mpumalanga and Limpopo Provinces red veld rats, Aethomys chrysophilus, Namaqua rock mice and Natal multimammate mice, Mastomys natalensis were good hosts of H. leachi and Rhipicephalus simus. Haemaphysalis leachi was the only tick recovered from animals in all three provinces.

Seasonal occurrence and production effects of the biting louse Damalinia limbata on Angora goats and 2 treatment options.

Adult biting lice Damalinia limbata (Gervais 1844) were most numerous on Angora goats in southwestern Free State Province from November to May with the smallest numbers present during August. Nymphs were most numerous from January to March with the smallest numbers present during July. The largest proportion of adult lice was present on the ventral surface of goats during winter, when population numbers were lowest, and the largest proportion of nymphs during summer, when population numbers were highest. Infestation did not affect the body weight of goats, but adversely affected both the quantity and quality of mohair produced. A single treatment with deltamethrin, applied as a pour-on along the mid-line of the backs of the goats, effectively controlled infestation and resulted in a significant increase in mohair production compared with untreated goats. Deltamethrin sprayed along the sides of the animals was equally effective in controlling infestation.

Efficacy of orally administered powdered aloe juice (Aloe ferox) against ticks on cattle and ticks and fleas on dogs.

The efficacy of orally administered powdered aloe juice (Aloe ferox) was evaluated against ticks on cattle and against ticks and fleas on dogs. Twelve calves were each infested over a 25-day period with approximately 4000 larvae of Rhipicephalus (Boophilus) decoloratus and allocated to 3 groups of 4 calves each. Three days after the last larval infestation and daily for 22 days thereafter, the calves in 1 group were fed 5 mg/kg body weight and those in another 25 mg/kg body weight of powdered aloe juice incorporated in game maintenance pellets, while the animals in the 3rd group received only pellets. Detached female ticks were collected daily and counted and the weights and the fertility of groups of 50 engorged female ticks collected from the animals were ascertained. The powdered aloe juice in the game maintenance pellets had no effect on the tick burdens of the calves or on the fertility of the ticks. Six dogs, in each of 2 groups, were treated daily for 15 consecutive days, commencing on Day -5 before the 1st tick infestation, with either 0.39 g or 0.74 g of powdered aloe juice, administered orally in gelatin capsules, while a 3rd group of 6 dogs served as untreated controls. All the dogs were challenged with Haemaphysalis leachi on Days 0 and + 7, and with Ctenocephalides felis on Days + 1 and + 8, and efficacy assessments were made 1 day after flea and 2 days after tick challenge, respectively. Treatment was not effective against ticks or fleas on the dogs.

Katkor cat litter, a non-invasive method of collecting cat urine for phosphate determination.

This study was done to compare the collection of cat urine, for phosphate concentration determination, by catheterisation with that via a proprietary cat litter (Katkor). The passage of urine through the litter or its retention in the litter for a period of 2 hours did not affect the concentration of phosphates compared with that of the original sample. Apart from a small volume of urine trapped in the litter by capillary action, and some urine adhering to the funnel in which the litter was placed, the litter proved to be an excellent medium for routine urine collection from cats, and more especially as an alternative to catheterisation when regular collection from a particular cat is required.

Elephant shrews as hosts of immature ixodid ticks.

Two hundred and seventy-three elephant shrews, consisting of 193 Elephantulus myurus, 67 Elephantulus edwardii and 13 animals belonging to other species, were examined for ixodid ticks at 18 localities in South Africa and Namibia. The immature stages of Ixodes rubicundus, Rhipicentor nuttalli, Rhipicephalus warburtoni and a Rhipicephalus pravus-like tick were the most numerous of the 18 tick species recovered. Substantial numbers of immature Rhipicephalus arnoldi, Rhipicephalus distinctus and Rhipicephalus exophthalmos were also collected from elephant shrews at particular localities. Larvae of I. rubicundus were most numerous on E. myurus in Free State Province from April to July and nymphs from June to October. Larvae of R. nuttalli were most numerous on these animals during April, May, August and September, and nymphs in February and from April to August. The immature stages of R. warburtoni were collected from E. myurus only in Free State Province, and larvae were generally most numerous from December to August and nymphs from April to October.

A laboratory comparison of the life cycles of the dog ticks Haemaphysalis leachi and Rhipicephalus sanguineus.

Engorged female Haemaphysalis leachi and Rhipicephalus sanguineus as well as their eggs, flat and engorged larvae and nymphs were incubated at combinations of five temperatures and three relative humidities. Mean pre-oviposition periods for H. leachi varied between 4.3 days and 12.1 days and for R. sanguineus between 4.8 days and 21.0 days. Haemaphysalis leachi converted up to 65.7% of their body mass into eggs and produced up to 16.3 eggs/mg body mass, with 4801 eggs the maximum number deposited by a single female. Peak egg production of 520 eggs/day was recorded 3 days after the commencement of oviposition. Rhipicephalus sanguineus converted up to 68.1% of their body mass into eggs and produced up to 17.2 eggs/mg body mass, with a maximum of 3,232 eggs, and peak egg production of 400 eggs/day 4 days after the commencement of oviposition. Mean incubation periods for eggs of H. leachi varied between 15.5 days and 66.7 days, and for R. sanguineus between 19.0 days and 72.0 days. Mean pre-moult periods for engorged larvae and nymphs of H. leachi varied between 14.0 days and 192.0 days, and 13.0 days and 41.0 days respectively, and for R. sanguineus between 9.5 days and 36.5 days, and 15.0 days and 44.5 days respectively. Allowing 7 days for female engorgement and 7 days for hardening of the exoskeletons and mouthparts of each of the three parasitic stages before they attach to a host, the life cycle of H. leachi would require 97-190 days and that of R. sanguineus 99-236 days to complete at the various regimes of temperature and relative humidity. The greatest proportion of H. leachi larvae engorging on mice detached between 18:00 and 19:00 on the first day of detachment and between 06:00 and 08:00 in the morning and 14:00 and 18:00 in the afternoon of the following day, while the greatest proportion of nymphs engorging on dogs detached around 19:00 on the first day of detachment and between 13:00 and 17:00 on the following day. The greatest proportion of R. sanguineus larvae engorging on dogs detached between 11:00 and 21:00 on the second day of detachment, and the greatest proportion of nymphs detached between 03:00 and 5:00 on the second and third days of detachment.

Larval biology of rhipicephalus (Boophilus) decoloratus (Acarina: Ixodidae) in Free State Province, South Africa.

The objective of this study was to determine certain aspects of the biology of Rhipicephalus (Boophilus) decoloratus larvae under laboratory and field conditions. Larvae allowed 48 h to select a vertical questing substrate preferred 90 cm rods in length to those of 60 or 30 cm, while in a separate experiment migration from rods 5 cm or 25 cm in length to rods 45 cm in length continued between 48 h and 72 h after larval release. Hatching of the larval progeny of engorged female ticks exposed to ambient field temperatures during the period June to August, occurred synchronously during the third or fourth week of November. With a single exception, larvae that hatched during November and between April and July survived for 38 days or longer, while those that hatched from December to March survived for 31 days or less. Questing larvae were present on vegetation throughout the year, with most being recovered during January and February. Parasitic larvae were present on cattle from October to May with most being collected during January and February.

Fleas of elephant shrews (Mammalia, Macroscelididae) and a new host and locality record for Macroscelidopsylla albertyni De Meillon & Marcus, 1958 (Siphonaptera, Chimaeropsyllidae).

Fleas collected from the elephant shrews Elephantulus edwardii (A. Smith, 1839) in the Western Cape Province, Elephantulus myurus Thomas & Schwann, 1906 in Free State Province, and an Elephantulus of undetermined species in the Eastern Cape Province, South Africa are recorded in this paper. Five flea species were recovered of which Demeillonia granti (Rothschild, 1904) was the most numerous and prevalent. It was followed by Macroscelidopsylla albertyni De Meillon & Marcus, 1958, collected only from E. edwardii. Both this elephant shrew and the locality are new records for M. albertyni. Chiastopsylla octavii (Rothschild, 1904), Listropsylla agrippinae (Rothschild, 1904), and a female flea of the Ctenocephalides felis group were accidental infestations. The sex ratio of D. granti was 0.86 on both male and female elephant shrews, while that of M. albertyni on E. edwardii was 0.83.

Comparison of 3 tests to detect acaricide resistance in Boophilus decoloratus on dairy farms in the Eastern Cape Province, South Africa.

The susceptibility of the larval offspring of engorged female Boophilus decoloratus, and of the engorged females, collected from cattle on the dairy farms Brycedale, Sunny Grove and Welgevind in the Eastern Cape Province, South Africa, was tested against the acaricides amitraz, chlorfenvinphos and cypermethrin. Resistance was determined by means of the Shaw Larval Immersion Test (SLIT) for larvae and the Reproductive Estimate Test (RET) and Egg Laying Test (ELT) for adults. At Brycedale the tests all indicated resistance to chlorfenvinphos, and RET and ELT indicated resistance to amitraz and emerging resistance to cypermethrin. At Sunny Grove, B. decoloratus was resistant to cypermethrin using SLIT and exhibited emerging resistance to chlorfenvinphos with SLIT and to cypermethrin with both RET and ELT At Welgevind, resistance was recorded against chlorfenvinphos (SLIT) and against cypermethrin (ELT), and emerging resistance against permethrin (RET). The results obtained with RET and ELT were generally comparable, but often differed from those obtained with SLIT. Resistance could be detected within 7 days with ELT compared to 42 days with RET and 60 days with SLIT.

The efficacy of collars impregnated with flumethrin and propoxur against experimental infestations of adult Rhipicephalus sanguineus on dogs.

The efficacy of 2 sets of collars (Kiltix Collar, Bayer AG), containing different plasticisers and impregnated with the acaricides flumethrin (2.25%) and propoxur (10%), was compared against adult Rhipicephalus sanguineus on experimentally infested, kennelled dogs. Thirty individually penned dogs were infested with 25 male and 25 female, unfed R. sanguineus. On the following day they were allocated to 3 groups of 10 dogs each on the magnitude of their tick burdens. Two days after infestation, medicated collars containing 1 of the plasticisers were fitted to 10 of the dogs and similar collars containing the other plasticiser were fitted to 10 others. The remaining 10 dogs were the untreated controls. Seven and 28 days after having fitted the collars, all dogs were re-infested with 50 unfed adult ticks of both sexes, and again at approximately 28-day intervals up to the 5th month, and then at approximately 14-day intervals during the 6th month. Efficacy was determined by comparing the mean number of live, attached ticks on the untreated control group with those on the collared dogs 2 days after each re-infestation. Immediate efficacy of the collars (Day +2) was > 95%, and residual efficacy was > 98% up to and including Day +114, and > 93% up to Day +170 on both groups of collared dogs. The mean tick counts on the 2 groups of collared dogs did not differ significantly (P < 0.0001) for any of the assessment days.

Hosts, seasonal occurrence and life cycle of Rhipicentor nuttalli (Acari: Ixodidae).

There are only two species worldwide within the genus Rhipicentor, namely Rhipicentor bicornis and Rhipicentor nuttalli and both occur only in Africa. Rhipicentor nuttali has a widespread distribution in South Africa and the present investigation was initiated to elucidate its host preference, seasonality and life cycle. Rock elephant shrews, Elephantulus myurus were examined for ticks at four localities in the Free State Province, one in Gauteng Province and two in Limpopo Province, South Africa. Cape elephant shrews, Elephantulus edwardii were examined at two places in the Western Cape Province, and a single specimen of the bushveld elephant shrew, Elephantulus intufi was examined in central Namibia. Small mammals of other species were also examined at two of these localities. The majority of E. myurus at two sites in the Free State, at the locality in Gauteng and both sites in Limpopo Province were infested with larvae and/or nymphs of R. nuttalli, while the single E. edwardii examined at one site in the Western Cape Province and the single E. intufi examined in Namibia were infested with nymphs of this tick. Not one of the other small animals was infested. Although larvae and nymphs of R. nuttalli were present on E. myurus throughout the year, the former were generally most numerous during the period March to September, and the latter during May to October. The preferred hosts of the adults are domestic dogs, leopards, Panthera pardus and South African hedgehogs, Atelerix frontalis. Adult females engorged on Atelerix frontalis in 16-32 days and, after a preoviposition period of 2-4 days, produced approximately 170,00 eggs during the following 60-70 days. The average incubation period of the eggs was 59 days. Larvae engorged on E. myurus in 4-10 days and moulted to nymphs 12-20 days later. Nymphs required 11-15 days to engorge on E. myurus and moulted to adults 32-47 days later. Allowing 14 days for the exoskeletons and mouthparts of each of the three parasitic stages to harden before they can attach to a host, the life cycle took approximately 214 days to complete in the laboratory. The length of this period, considered in conjunction with the times of maximum seasonal occurrence of the immature stages, indicates that the life cycle probably takes a year to complete in the field.

Acaricide resistance profiles of single- and multi-host ticks from communal and commercial farming areas in the Eastern Cape and North-West Provinces of South Africa.

A field study (February 2000 to August 2001) was conducted on communal and commercial farms in the Eastern Cape and North-West Provinces of South Africa to detect the levels of tick resistance to commonly used acaricides. The larvae obtained from engorged females of the one-host tick Boophilus decoloratus, the two-host tick Rhipicepalus evertsi evertsi and the three-host ticks Amblyomma hebraeum and Rhipicephalus appendiculatus were tested against various concentrations of amitraz, chlorfenvinphos and cypermethrin using the Shaw Larval Immersion Test method. Ticks from the communal farms showed higher levels of resistance to cypermethrin and some resistance to chlorfenvinphos whilst no resistance was detected against amitraz. However, ticks from commercial farms were equally resistant to amitraz, chlorfenvinphos and cypermethrin. The B. decoloratus populations tested were considerably more resistant to all the acaricides tested than the R. evertsi evertsi, A. hebraeum and R. appendiculatus populations. This supports the hypothesis that single-host ticks develop resistance faster than multi-host ticks. This trend was recorded on most of the farms where single- and multi-host ticks co-existed. It was concluded that the use of acaricides at high frequencies and high concentrations was one of the main causes of tick resistance in the study areas. Possible factors which caused the resistance problems are discussed and acaricide management strategies recommended.