Efficacy of fipronil in the treatment of pediculosis in laboratory rats

As parasitized rodents are not desirable experimental objects, it is important to maintain parasite-free laboratory rodent colonies. Faced with the task of eliminating pediculosis from a conventional laboratory rat colony whose individuals were intended to be used in scientific research, a drug treatment was needed which did not, or minimally, interfere with experimental results. Fipronil, a GABA(A) antagonist, is an effective drug against lice, fleas and mites currently used in domestic species. Fipronil is not absorbed, has a wide safety margin and is topically applied. The aim of this study was to treat an infected colony with Frontline Spray (0.25%-w/v-fipronil) in order to evaluate its efficacy against lice. Rats were sprayed with Frontline only once. Special procedures to prevent cross-contamination between cages were not used. Neither lice nor nits were found during any post-treatment examination. In addition, no complications were reported by any researcher after using the treated rats in their experiments. The results of this study demonstrate that fipronil in topical formulations is effective for treatment and control of sucking and biting lice infestations on laboratory rats.     

云南省吸虱昆虫区系及物种多样性

吸虱是寄生于真兽类哺乳动物体表的专性吸血寄生虫,广布于世界各地。云南省已知吸虱昆虫9科13属44种,分别占中国已知吸虱科、属、种的81.82%,59.09%,45.83%。文章参考大量相关文献,从分类阶元、特有物种、动物地理区划和宿主动物4个方面分析云南省吸虱的物种多样性。云南省吸虱特有种有13种,占云南省已知吸虱种类的29.55%,27种为东洋种,15种为古北和东洋两界兼有种,广布种9种。吸虱在5个地理小区的分布,以横断山中部和横断山南部2个地理小区的吸虱物种多样性较高,其它3个区的物种多样性较低。相对于全国而言,云南省吸虱物种多样性较高,吸虱的宿主动物种类丰富。但蚤、恙螨和革螨等其它体表寄生虫相比较,兽类宿主动物体表吸虱的物种多样性明显低于其它体表寄生虫,1科(属)阶元的吸虱其宿主多为相对一致的1个科(属)动物阶元,反映了吸虱宿主特异性较高的事实,吸虱昆虫与其对应的宿主动物已经形成了比较稳定的"一对一"的寄生关系,这是吸虱昆虫与其宿主动物协同进化的生态学表现。     

Geographical structuring of feather mite assemblages from the Australian brush-turkey (Aves: Megapodiidae)

Populations of a host species may exhibit different assemblages of parasites and other symbionts. The loss of certain species of symbionts (lineage sorting, or "missing-the-boat") is a mechanism by which geographical variation in symbiont assemblages can arise. We studied feather mites and lice from Australian brush-turkeys (Aves: Megapodiidae: Alectura lathami) and expected to observe geographical structuring in arthropod assemblages for several reasons. First, because the brush-turkey is a sedentary ground-dwelling bird, we predicted that geographically close host populations should share more similar arthropod assemblages than distant ones. Second, because brush-turkeys do not brood their young, vertical transfer of arthropods is unlikely, and brush-turkeys probably acquire their mites and lice at social maturity through contact with other birds. Young birds could disperse and found new populations without carrying complete sets of symbionts. We predicted that young birds would have fewer species of arthropods than older birds; in addition, we expected that males (which are polygynous) would have more species than females. Birds were sampled from 12 sites (=populations) along the east coast of Queensland, Australia, that were separated by a distance of 12.5-2,005 km. In total, 5 species of mites from the Pterolichidae and 1 species from the Ascouracaridae were found. Two species of lice were collected but in numbers too low to be statistically useful. Differentiation of mite assemblages was evident; in particular, Leipobius sp. showed 100% prevalence in 3 host populations and 0% in the remaining 9. A dendrogram of brush-turkey populations based on mite assemblages showed 2 geographically correlated clusters of sites, plus 1 cluster that contained 2 sites near Brisbane and 1 approximately at a distance of 1,000 km. There was no strong effect of host age or sex on number of mite species carried. Horizontal transfer of feather mites by hippoboscid flies, in addition to physical contact between hosts, may play a role in homogenizing symbiont assemblages within populations.     

Seasonal studies on commensal rats and their ectoparasites in a rural area of Egypt: the relationship of ectoparasites to the species, locality, and relative abundance of the host.

The present study was carried out in 3 villages, namely Kafr Ayoub Soliman, Kafr Ibrahim El-Aidi, and El-Sa'adat, Sharqiya Governorate, Egypt. A total of 519 rats was collected from the 3 study sites: 46.6% Rattus rattus, and 53.4% Rattus norvegicus. A total of 20,643 ectoparasites was recovered from R. rattus: 33.3% mites, 33.8% fleas, and 32.9% lice. From R. norvegicus a total of 40,997 ectoparasites was recovered: 28.9% mites, 31% fleas, and 40.1% lice. Three common mite species were recovered from both rat hosts, i.e., Ornithonyssus bacoti, Radfordia ensifera, and Laelaps nuttalli. Three common flea species were also recovered from both rat hosts, i.e., Echidnophaga gallinacea, Leptopsylla segnis, and Xenopsylla cheopis. Polyplax spinulosa was the only dominant louse species that infested both rat hosts. Rats did not show a definite breeding season, and the seasonal rat indices were generally low in different study sites. There were no significant differences between the prevalence of each of mites, fleas, and lice in both rat species. The total general indices of mites and fleas, on the other hand, was significantly higher in R. norvegicus. The general index of X. cheopis was high and ranged between 5.9 in R. rattus and 14.5 in R. norvegicus. Season-related changes were observed in the general index of each of L. segnis infesting both rat species and R. ensifera and O. bacoti infesting R. norvegicus. The prevalence and general indices of some ectoparasites showed differences related to the locality of their rat hosts. Seasonal changes in the general indices of some ectoparasites paralleled seasonal changes in the relative abundance of their rat hosts.     

Ectoparasites in rodents of the urban region of Belo Horizonte, MG. III. Fleas, Anoplura and Acari indices in Rattus norvegicus norvegicus

The total and specific indices of fleas, lice and mites were determined for ectoparasites on Rattus norvegicus norvegicus capture in urban areas of Belo Horizonte, Minas state, Brazil, from June 1980 to September 1982. In view of the limiting or critical values attributed to flea indices above all the "cheopis" index, proposed by several authors as a complementary measure for bubonic plague surveillance, the community of Belo Horizonte would have been exposed to this infection. The annual total indices ranged from 0.3 to 2.4 and the prevalent flea was Xenopsylla cheopis (99.2%), with the highest indices coinciding with the late dry-cool season. On two occasions, in this period, the community would have remained highly exposed to infection, since the index-limits were superseded: 8.8 (October 1980) and 6.2 (September 1982). It is suggested that preventive measures, such as protection against rat insecticide treatment may be efficiently applied in the late dry-cool season, or previous to the rainy season, before the elimination of rats. Reports on indices of lice and mites are important as they may establish index-limits for certain infections exclusive to rodents.     

Fossil lice (Insecta: Phthiraptera) reconsidered

Abstract.  Five papers describing fossils considered to be Phthiraptera (lice) by their authors are reviewed. We place the specimens described in three papers in the Acari (mites) and regard them as probably not fossils. A fourth paper describes what appears to be a fossil insect. However, we do not consider it to be a louse. The fifth paper describes a more recent fossil that differs little from extant lice.     

Ozobranchus jantseanus (Clitellata: Ozobranchidae) from Reeve’s Turtle,Mauremys reevesii: New Annelid Fauna in Korea

Turtle leeches have not been recorded in Korea, although they occur in geographically adjacent countries including China and Japan. This study describes a turtle leech, Ozobranchus jantseanus (Clitellata: Ozobranchidae), found from Reeve’s turtle (Mauremys reevesii) in Korea. Of the 143 Reeve’s turtles collected from the freshwater reservoir in Jinju City, Gyeongsangnam-do, Korea, 95 unidentified leeches were found in 8 (5.6%) individuals. The leeches had 22 somites with 11 pairs of externally exposed branchiae, body-sized posterior suckers, and spines on the dorsal surface. We identified these leeches as Ozobranchus jantseanus Oka, 1912 (Clitellata: Ozobranchidae). This species of turtle leeches found in Korea may fill the gap in the biodiversity of East Asian annulus.     

The incidence of predation on lake-dwelling leeches

SUMMARY. 1. Erpobdella octoculata (L.), Glossiphonia complanata (L.) and Helobdella stagnate (L.) were eaten readily by larval and adult dytiscid beetles, larval caddisflies and Sialis , nymphal odonatans and various fish in laboratory experiments.
2. A serological technique showed that very few lake-collected specimens of these predatory taxa, plus triclads, leeches and stone fly nymphs, had been feeding on leeches.
3. A literature survey of lake studies on fish diet indicated that usually less than 6% of individuals with gut contents had eaten leeches. Few detailed records of waterfowl feeding on leeches have been documented.
4. It is concluded that predation pressure on lake-dwelling leeches is light, and is more severe from fish than invertebrates, less on populations inhabiting stony shores than in vegetation, and greater on the erpobdellid than the two glossiphoniid species.     

Housing and dustbathing effects on northern fowl mites (Ornithonyssus sylviarum) and chicken body lice (Menacanthus stramineus) on hens

Hen housing (cage or cage-free) did not impact overall abundances of northern fowl mites, Ornithonyssus sylviarum (Canestrini & Fanzago) (Acari: Macronyssidae), or chicken body lice, Menacanthus stramineus (Nitzsch) (Phthiraptera: Menoponidae). Cage-free hens received a dustbox with sand plus diatomaceous earth (DE), kaolin clay or sulphur. Weekly use varied from none to 100% of hens; 73% of hens used the dustbox at least once. Ectoparasite populations on dustbathing hens (users) were compared with those on non-user cage-free and caged hens. All materials reduced ectoparasites on user hens by 80-100% after 1 week of dustbox use. Diatomaceous earth and kaolin failed to reduce ectoparasites on non-user hens, and ectoparasites on user hens recovered after dustbox removal. A sulphur dustbox eliminated mites from all hens (including non-users) within 2-4 weeks. Residual sulphur controlled mites until the end of the experiment (up to 9 weeks), even after the dustbox was removed. Louse populations on hens using the sulphur dustbox were reduced in 1-2 weeks. Residual sulphur effects were less evident in lice, but the use of a sulphur dustbox by a higher proportion of hens extended louse control to all hens. This is the first experimental study to show that bird dustbathing in naturally and widely available dust materials (particularly kaolin) can suppress ectoparasites and thus the behaviour is probably adaptive.     

Ectoparasites from elk (Cervus elaphus nelsoni) from Wyoming

Hides of nine elk, collected during the winter of 1986-1987 from the National Elk Refuge, Wyoming (USA) were examined for ectoparasites. Parasites recovered were mites, Psoroptes sp. (five elk); lice, Solenopotes ferrisi and Bovicola (Bovicola) longicornis (seven elk); and winter ticks, Dermacentor albipictus (nine elk). Three elk with severe scabies had an estimated 0.6 x 10(6), 3.8 x 10(6) and 6.5 x 10(6) mites, respectively. Densities of mites were much higher in skin regions with severe dermatitis. Skin lesions on elk with scabies consisted of dense, often moist, scabs extending along the dorsal and lateral thoracic regions of the body. Lesions attributed to winter ticks consisted of broken hair and alopecia on the dorsal portion of the lower neck, often extending in a "collar" around the neck.     

External parasites of raptors (Falconiformes and Strigiformes): identification in an ex situ population from Mexico

Raptorial birds harbor a variety of ectoparasites and the mayority of them are host specific. The aim of this study was to identify the ectoparasites of captive birds of prey from Mexico, as well as to verify their impact in the health of infested birds. Raptorial birds were confiscated and kept in captivity at the Centro de Investigación y Conservación de Vida Silvestre (CIVS) in Los Reyes La Paz, Mexico State. Seventy-four birds of prey (66 Falconiformes and eigth Strigiformes) of 15 species were examined for the presence of ectoparasites. We examined both juvenile and adult birds from both sexes. The overall prevalence was 16.2%; 66.7% of raptors were infested with a single type of external parasite. Lice were the most prevalent ectoparasites (91.7%), followed by feather mites and fleas (8.3%). Degeeriella fulva (72.7%), Craspedorrhynchus sp. (45.4%) and Strigiphilus aitkeni (9.1%) (Ischnocera, Philopteridae) were recovered from wings, head and neck regions of red-tailed hawk (Buteo jamaicensis), Swainson's hawk (B. swainsoni), Harris's hawk (Parabuteo unicinctus) and Barn owl (Tyto alba). Low lice infestation level was observed. Nymphs and females of feather mites Kramerella sp. (Pterolichoidea, Kramerellidae) were recovered solely from Barn owl (T. alba); while one Caracara (Caracara cheriway) was infested by the sticktight flea Echidnophaga gallinacea (Siphonaptera, Pulicidae). No clinical signs were observed in any infested bird. Probably the periodic use of organophosphorates was responsible of the low prevalence and lice infestation levels. The diversity of external parasites illustrates the importance of detailed revision of incoming and long-term captive raptors as part of responsible captive management. Five new hosts and geographic records are presented.     

Structure and seasonal dynamics of the biotic community ectoparasites of the bank vole in the Il'men'-Volkhov lowland

A biodiversity, seasonal dynamics and parasite load of a single individual and local population of the bank vole (Clethrionomys glareolus) were studied in coniferous and mixed forests of the Ilmen-Volkhov lowland (neighborhood of Oskuy village, Chudovo region, Novgorod Province) in the period from June 1999 till May 2002. The Gero's traps were used for collecting the host. Lines of traps stood in each place during 3-5 days and were checked twice a day. Trapping of micromammalian hosts and collecting of parasites took place each month, except a few gaps. Total number of collected animals 2854 including 1405 bank voles. The 29 ectoparasite species were recorded on the bank vole in the area of study. Among some mites and fleas a few species are accidental parasites probably accepted by voles from other species of animals. In the Oskuy area, the bank voles are the main and additional hosts of 25 ectoparasite species: fleas--8, lice--1, ixodid ticks--2, gamasid mites--7, acariform mites 7. Species composition of ectoparasites, their occurrence and abundance change during the year. Seasonal changes of abundance and occurrence indices are most expressed in the temporary ectoparasites (ixodid ticks, chiggers, gamasid mites), while in the permanent parasites (lice, acariform mites: Myobiidae, Myocoptidae, Listrophoridae), the seasonal fluctuations of indices are displayed in a less scale. Most vole specimens were infected with this or that ectoparasite species. The parasitocenosis on an individual specimen usually included less than 10 species of the total number 29 species recorded on the bank vole in the area investigated. One ectoparasite species was recorded on 21% of host specimens, 2-5 ectoparasite species were found on 71% of host individuals. Maximal number of ectoparasite species (10 species) was registered on one specimen only. The parasite load was dispersed unevenly among the infected voles. Mean number of parasites of all species on a host individual varied from 124 to 295. The highest grade of parasites (237-297 parasite specimens) was found in the voles with 7-10 species of parasites.     

Melanocortin‐1‐receptor (MC1R) variation is not associated with parasite burden in a neotropical bird,the bananaquit (Coereba flaveola)

It has been suggested that selection on melanocortin‐1‐receptor (MC1R) polymorphism, a common cause of melanic colour variation in vertebrates, results from pleiotropic effects of the gene in the immune system. Here we present the first test of whether MC1R variation is associated with differences in parasite abundance in a natural population. Bananaquits (Coereba flaveola) (Linnaeus, 1758) living on Grenada in the Caribbean exhibit a melanic plumage dimorphism as a result of a mutation in MC1R. The proportion of black individuals increases clinally towards the central, wetter parts of the island. We captured bananaquits through the cline and quantified parasite abundances. Avian malaria, feather mites, and mallophaga lice varied significantly in abundance across the cline; however, neither these infections, nor coccidia, nor arboviruses showed overall differences between the morphs. Feather mites tended to be more abundant on black individuals, in areas where the black morph was more common. This may result from differences in microhabitat use by the two morphs. These patterns do not support the idea that MC1R variation in itself results in differing susceptibility to parasites. © 2013 The Linnean Society of London     

Species composition of the parasitic cenoses of gerbils

Complex studies of parasitic cenoses of four species of gerbils were carried out in Turkmenia. Over 60 forms of parasites were found out as follows: three species of blood parasites, 12 species of Coccidia, 8 species of cestodes, 12 species of nematodes, one species of Acanthocephalus, three species of chigger mites, 15 species of gamasid mites, 6 species of ixodid ticks, fleas and lice. The list of species of parasites with regard to their hosts is provided.     

Ectoparasites of the Irish stoat

A sample of 196 Irish stoats Mustela ermineae hibernica Thomas & Barrett-Hamilton (Carnivora: Mustelidae) were examined and yielded 2580 arthropod ectoparasites, including 1819 larval mites Neotrombicula autumnalis (Shaw) from a single host. Other ectoparasites recovered included lice (99% Trichodectes ermineae (Hopkins], ticks (mostly Ixodes hexagonus Leach) and four species of fleas. The ticks and fleas were considered to have come mainly from nests of other hosts. The flea species did not reflect the status of their usual hosts in the diet of stoats, but did reflect the stoats' use of their usual hosts' habitat.     

中国云南洱海周边褐家鼠的体表寄生虫群落组成

褐家鼠Rattus norvegicus可能是云南省部分鼠疫流行区的储存宿主之一, 其体表的某些寄生虫种类可能是人类疾病的传播媒介。为了解洱海周边地带褐家鼠的体表寄生虫群落, 并对其医学和兽医学的重要性进行描述。用U检验和相关分析的统计方法对2003-2004年采自云南洱海（中国滇西北著名的淡水湖泊）周边地区的431头褐家鼠的体表寄生虫群落进行了研究。用构成比（C）, 侵染率(P)和平均丰富度(A)反映体表寄生虫的流行和密度状况。调查点位于我国11大鼠疫自然疫源地之一, 此地也是我国恙虫病和流行性出血热的流行地区。结果表明: 431头褐家鼠中307头寄生有体表寄生虫, 侵染率为71%。采集到的体表寄生虫有47种, 包括23种恙螨、16种革螨、6种蚤和2种吸虱, 其中16种以前已经被证明是人类疾病的媒介。结果提示褐家鼠的体表寄生虫物种多样性高。     

Mites and birds: diversity, parasitism and coevolution

Ectoparasites play important roles in the lives of birds. Among these parasites, mites offer unique potential because of their extraordinary ecological and evolutionary diversity. However, the basic biology of most mites is poorly understood, and misleading extrapolations are sometimes made from better studied systems involving lice and fleas. Most importantly, not all bird-associated mites are parasitic; indeed, recent research suggests that some might even be beneficial. Here, we summarize what is known about the diversity of bird-mite relationships, and highlight how mites provide an ideal tool for the study of host life histories, sexual selection, immunocompetence and cospeciation.     

Managing plague on prairie dog colonies: insecticides as ectoparasiticides

Human health practitioners and wildlife biologists use insecticides to manage plague by suppressing fleas (Siphonaptera), but insecticides can also kill other ectoparasites. We investigated effects of deltamethrin and fipronil on ectoparasites from black‐tailed prairie dogs (Cynomys ludovicianus, BTPDs). In late July, 2018, we treated three sites with 0.05% deltamethrin dust and 5 sites with host‐fed 0.005% fipronil grain. Three non‐treated sites functioned as experimental baselines. We collected ectoparasites before treatments (June‐July, 2018) and after treatments (August‐October, 2018, June‐July, 2019). Both deltamethrin and fipronil suppressed fleas for at least 12 months. Deltamethrin had no detectable effect on mites (Arachnida). Fipronil suppressed mites for at least 12 months. Lice (Phthiraptera) were scarce on non‐treated sites throughout the study, complicating interpretation. Concentrating on eight sites where all three ectoparasites where found in June‐July, 2018 (before treatments), flea intensity was greatest on BTPDs carrying many lice and mites. These three ectoparasites co‐occurred at high numbers, which might facilitate plague transmission in some cases. Lethal effects of insecticides on ectoparasite communities are potentially advantageous in the context of plague management.     

Ectoparasites of rodents of the urban region of Belo Horizonte, MG. II. Variations of the infestation indices in Rattus norvegicus norvegicus

The indices of infestation by the mites Echinolaelaps echidninus and Laelaps nuttalli, the louse Popyplax spinulosa and the flea Xenopsylla cheopis, obtained monthly, from June 1980 to September 1982, on Rattus norvegicus norvegicus in the city of Belo Horizonte, Minas Gerais state, Brazil were related to seasonal period, sex of the host and area of capture. Mites and insects showed different behaviour in relation to these factors. Only the fleas and lice exhibit significant association between the rodents' infestation and the seasonal period, or between the infestation and the rodents' sex or else a variation of the distribution by the three main areas of capture. The fleas showed the highest indices of infestation in the warm-rainy season (October to March) while the infestation by the lice was more prevalent in the dry-cool season. The climatic factors most related with the hosts' infestation were, in decreasing order, rainfall, temperature and relative humidity. Fleas and lice preferentially infested male rodents, being infestation by X. cheopis highly significant.     

Rodent sociality and parasite diversity

The risk of parasitism is considered to be a general cost of sociality and individuals living in larger groups are typically considered to be more likely to be infected with parasites. However, contradictory results have been reported for the relationship between group size and infection by directly transmitted parasites. We used independent contrasts to examine the relationship between an index of sociality in rodents and the diversity of their macroparasites (helminths and arthropods such as fleas, ticks, suckling lice and mesostigmatid mites). We found that the species richness of directly transmitted ectoparasites, but not endoparasites, decreased significantly with the level of rodent sociality. A greater homogeneity in the biotic environment (i.e. a reduced number of cohabiting host species) of the more social species may have reduced ectoparasites' diversity by impairing ectoparasites transmission and exchange. Our finding may also result from beneficial outcomes of social living that include behavioural defences, like allogrooming, and the increased avoidance of parasites through dilution effects.