Relapsing fever – a forgotten disease revealed

Borrelial relapsing fever was once a major worldwide epidemic disease that made a significant impact on Livingstone during his epic travels through Africa and throughout Europe. Indeed, the term ‘relapsing fever’ was first used to describe clinical cases of this disease in Edinburgh. During the last century, we have witnessed the demise of the louse‐borne infection, largely through improving standards of living resulting in a reduction in body lice, the vector for Borrelia recurrentis [louse‐borne relapsing fever (LBRF)]. The tick‐borne zoonotic form of the disease persists in endemic foci around the world [tick‐borne relapsing fever (TBRF)]. Indeed, TBRF is reportedly the most common bacterial infection from Senegal and listed within the top ten causes of mortality in children under five in Tanzania. In Ethiopia, LBRF is again within the top ten causes of hospital admission, associated with significant morbidity and mortality. Despite these figures, many now regard relapsing fever as an unusual tropical disease. Certainly, recent cases have been imported following travel from endemic zones. More surprisingly, cases have been reported following family reunions in Colorado, USA. A further case was reported from the Mt Wilson observatory in Los Angeles, USA. In many regions, the infection is zoonotic with natural reservoirs in several vertebrate species. In West Africa, infection is again primarily zoonotic. Whether those species found predominantly in East Africa are zoonoses or are infections of humans alone is still debated, however, the life cycle may be determined by the feeding preferences of their arthropod vectors.     

Prevalence of pediculosis and scabies in preschool nursery children of Afyon, Turkey

Scabies and pediculosis are ubiquitous, contagious, and debilitating parasitic dermatoses. The tendency of high prevalence of pediculosis and scabies among school and preschool age children has prompted us to conduct a head louse and scabies prevalence survey among preschool nursery children in our district. A school-based, crosssectional study was performed, with 1,134 children chosen for evaluation. All cases were evaluated by physical examination and a detailed, structured questionnaire. The infestation was found in 14 (1.2%) of 1,134 children; 9 (0.8%) with pediculosis capitis and 5 (0.4%) with scabies. We found that infestations were more frequent in children with mothers whose education levels were low. This indicates the necessity of an improvement in the economic and sociocultural status of the community and the promotion of hygiene concepts and practices in order to improve health of preschool age children.     

Change in carbon stable isotope ratios of the predatory bug Orius majusculus after dietary shifts

Orius majusculus Reuter (Hemiptera: Anthocoridae) is an important component of the pest predatory complex in arable crops in Mediterranean areas. It moves between crops searching for prey, and improving knowledge on its dispersal abilities will help to develop conservation biological control strategies. Stable isotope ratios may be used as a tool for tracking insect movements, as the isotopic composition of insect tissues changes to reflect that of their diet when they undergo dietary shifts on moving between isotopically distinct crops. We carried out laboratory diet switch experiments with a stable isotope approach to infer information on dispersal of O. majusculus individuals among C3 and C4 crops to better understand isotopic field data collections. Switching the aphid food source caused a quick change in δ¹³C signatures, regardless of the original and final food source. Changes in the δ¹³C ratio of O. majusculus after diet switching fitted with an exponential model that showed similar turnover rates, and thus half‐lives, between shifting diets up to 20 days. Subsequently, whereas individuals feeding on C4 aphids did not survive, turnover rate decreased in individuals that switched from C4 to C3 aphids. However, δ¹³C traces from the original source remained in the predator until 25 days after switching, and this is enough time to help determine the movement of O. majusculus between crops in the field and to plan the timing of predator sampling and crop practices that may enhance predator ecological services. Orius majusculus that switched to a maize aphid diet showed different turnover rates between sexes, although this did not influence the pattern of switchover.     

Controlling Myzus persicae with recombinant endophytic fungi Chaetomium globosum expressing Pinellia ternata agglutinin: using recombinant endophytic fungi to control aphids

Aims: Sap‐sucking insect pests have become the major threats to many crops in recent years; however, only a few biopesticides have been developed for controlling those pests. Here, we developed a novel pest management strategy, which uses endophytes to express anti‐pest plant lectins. Methods and Results: The fungal endophyte of Chaetomium globosum YY‐11 with anti‐fungal activities was isolated from rape seedlings. Pinellia ternata agglutinin (pta) gene was cloned into YY‐11 mediated by Agrobacterium tumefaciens. The positive transformants, as selected by antibiotic resistance, were evaluated using PCR and Western blot assay. We found that the recombinant endophytes colonized most of the crops, and the resistance of rape inoculated with recombinant endophytic fungi significantly inhibited the growth and reproduction of Myzus persicae. Conclusions: Our results showed that the recombinant endophytes expressing Pinellia ernata agglutinin (PTA) may endow hosts with resistance against sap‐sucking pests. Significance and Impact of the Study: This research may have important implications for using endophytes to deliver insecticidal plant lectin proteins to control sap‐sucking pests for crop protection.     

Molecular cloning and characterisation of a novel P-glycoprotein in the salmon louse Lepeophtheirus salmonis

The salmon louse, Lepeophtheirus salmonis, is a crustacean ectoparasite of salmonid fish. At present, sea louse control on salmon farms relies heavily upon chemical treatments. Drug efflux transport, mediated by ABC transporters such as P-glycoprotein (Pgp), represents a major mechanism for drug resistance in parasites. We report here the molecular cloning of a new Pgp from the salmon louse, called SL-PGY1. A partial Pgp sequence was obtained by searching sea louse ESTs, and extended by rapid amplification of cDNA ends (RACE). The open reading frame of SL-PGY1 encodes a protein of 1438 amino acids that possesses typical structural traits of P-glycoproteins, and shows a high degree of sequence homology to invertebrate and vertebrate P-glycoproteins. In the absence of drug exposure, SL-PGY1 mRNA expression levels did not differ between a drug-susceptible strain of L. salmonis and a strain showing a ~7-fold decrease in sensitivity against emamectin benzoate, the active component of the in-feed sea louse treatment SLICE (Merck Animal Health). Aqueous exposure of the hyposensitive salmon louse strain to emamectin benzoate (24h, 410 μg/L) provoked a 2.9-fold upregulation of SL-PGY1. Adult male lice of both strains showed a greater abundance of SL-PGY1 mRNA than adult females.     

Origin,acquisition and diversification of heritable bacterial endosymbionts in louse flies and bat flies

The γ‐proteobacterium Arsenophonus and its close relatives (Arsenophonus and like organisms, ALOs) are emerging as a novel clade of endosymbionts, which are exceptionally widespread in insects. The biology of ALOs is, however, in most cases entirely unknown, and it is unclear how these endosymbionts spread across insect populations. Here, we investigate this aspect through the examination of the presence, the diversity and the evolutionary history of ALOs in 25 related species of blood‐feeding flies: tsetse flies (Glossinidae), louse flies (Hippoboscidae) and bat flies (Nycteribiidae and Streblidae). While these endosymbionts were not found in tsetse flies, we identify louse flies and bat flies as harbouring the highest diversity of ALO strains reported to date, including a novel ALO clade, as well as Arsenophonus and the recently described Candidatus Aschnera chinzeii. We further show that the origin of ALO endosymbioses extends deep into the evolutionary past of louse flies and bat flies, and that it probably played a major role in the ecological specialization of their hosts. The evolutionary history of ALOs is notably complex and was shaped by both vertical transmission and horizontal transfers with frequent host turnover and apparent symbiont replacement in host lineages. In particular, ALOs have evolved repeatedly and independently close relationships with diverse groups of louse flies and bat flies, as well as phylogenetically more distant insect families, suggesting that ALO endosymbioses are exceptionally dynamic systems.     

中国云南部分小兽体表吸虱昆虫群落相似性及群落分类研究(英文)

应用系统聚类分析方法对云南省境内24种主要小型哺乳动物(小兽)体表吸虱昆虫群落相似性及群落分类进行了研究。研究中将每一种小兽体表的所有吸虱昆虫定义为一个相应的吸虱群落单位。结果表明,小兽体表吸虱群落结构简单,物种多样性很低。多数小兽有固定的吸虱种类寄生,其吸虱的宿主特异性高。在动物分类上隶属同一个属的小兽,其体表吸虱群落相似程度高,在系统聚类分析中大多被归为一类。在动物分类上近缘的小兽,其体表吸虱群落相似,优势虱种相同或相似,此情形尤其表现在鼠属、白腹鼠属、姬鼠属和绒鼠属。吸虱群落相似性大小与相应小兽宿主在动物分类地位上的近缘性高低呈现高度一致。从生态学角度来看,吸虱昆虫与其所寄生的小兽宿主动物之间存在密切的协同进化关系。     

Identity of <Emphasis Type="Italic">Menacanthus obrteli</Emphasis> Balát (Phthiraptera: Menoponidae) from the Savi’s warbler (Passeriformes: Sylviidae)

The louse Menacanthus obrteli Balát, 1981 is resurrected from synonymy as a valid species, with Locustella luscinioides, the Savi’s warbler, as the type-host. Both sexes of this louse species are redescribed and illustrated.     

Characterization of 10 microsatellite loci in an avian louse, Degeeriella regalis (Phthiraptera: Ischnocera: Philopteridae)

We isolated and characterized 10 polymorphic microsatellite loci in an ischnoceran louse, Degeeriella regalis, which parasitizes the threatened Galápagos hawk (Buteo galapagoensis) and other falconiform birds. The loci were screened across 30 individuals from two island populations in the Galápagos Islands. The number of alleles per locus ranged from two to 28. Polymorphic information content ranged from 0.14 to 0.94 and observed heterozygosity ranged from 0 to 0.67. These markers will be valuable in comparative population genetics studies in this species, which is the focus of a long-term population and disease ecology research program.     

SIMILARITY COMPARISON AND CLASSIFICATION OF SUCKING LOUSE COMMUNITIES ON SOME SMALL MAMMALS IN YUNNAN, CHINA

Abstract  The similarity and classification of sucking louse communities on 24 species of small mammals were studied in Yunnan Province, China, through a hierarchical cluster analysis. All the louse species on the body surface of a certain species of small mammals are regarded as a louse community unit. The results reveal that the community structure of sucking lice on small mammals is simple with low species diversity. Most small mammals usually have certain louse species on their body surface; there exists a high degree of host specificity. Most louse communities on the same genus of small mammals show a high similarity and are classified into the same group based on hierarchical cluster analysis. When the hosts have a close affinity in taxonomy, the louse communities on their body surface would tend to be similar with the same or similar dominant louse species (as observed in genus Rattus, Niviventer, Apodemus and Eothenomys ). The similarity of sucking louse communities is highly consistent with the affinity of small mammal hosts in taxonomy. The results suggest a close relationship of co-evolution between sucking lice and their hosts.