The effect of Lucilia sericata larval excretion/secretion (ES) products on cellular responses in wound healing.

Chronic wounds are still regarded as a serious public health concern, which are on the increase mainly due to the changes in life styles and aging of the human population. There are different types of chronic wounds, each of which requires slightly different treatment strategies. Nevertheless, wound bed preparation is included in treatment of all types of chronic wounds and involves tissue debridement, inflammation, and infection control, as well as moisture balance and epithelial edge advancement. Maggot therapy (MT) is a form of biological debridement which involves the application of live medical grade Lucilia sericata (Meigen, 1826) (Diptera: Calliphoridae) larvae. Whereas it was initially thought to act mainly through debridement, today MT is known to influence all four overlapping physiological phases of wound repair: homeostasis, inflammation, proliferation, and remodelling/maturing. During MT, medical-grade larvae are applied either freely or enclosed in tea-bag like devices (biobag) inside the wounds, which suggests that larva excretion/secretion (ES) products can facilitate the healing processes directly without the need of direct contact with the larvae. This review summarizes the relevant literature on ES-mediated effects on the cellular responses involved in wound healing.

Potential tick vectors for Theileria equi in Israel.

Theileria equi Mehlhorn and Schein, 1998 (Piroplasmida: Babesiidae) is an important tick-borne pathogen of horses that is highly endemic in many parts of the world, including Israel. The present study evaluated the potential roles of five hard tick species [Hyalomma excavatum Koch, 1844; Hyalomma marginatum Koch, 1844; Rhipicephalus turanicus Pomerantsev 1936; Rhipicephalus annulatus Say, 1821; Haemaphysalis parva (Neumann, 1897) (all: Ixodida: Ixodidae)], previously found to infest horses in Israel, in acting as vectors for piroplasmosis. For this, DNA was extracted from whole ticks and, when possible, from the salivary glands in each species (n = 10-59). Polymerase chain reaction amplification and sequencing of the 18S rRNA gene were used to detect T. equi in 48 of the 127 ticks (37.8%) and in 21 of the 90 extracted salivary glands (23.3%) in all five species. All but two sequences were classified as T. equi genotype A; the remaining two were classified as genotype D. The findings of this study point to Ha. parva and R. annulatus as potential novel vectors of T. equi, and suggest that parasite genotype selection occurs within the tick vector.

Bibliometric analysis of publications on house dust mites during 1980-2018.

BACKGROUND: The global prevalence of allergic diseases has increased dramatically in recent years and are now recognized as significant chronic diseases worldwide. One of the most important allergens that causes allergic diseases is house dust mites. OBJECTIVE: This study aims to present a bibliometric overview of research published on dust mites between 1980 and 2018. METHODS: Articles published from 1980 to 2018 were analyzed using bibliometric methods. The keywords "Dust mite*," and "Dermatophagoides" were used in the Web of Science (WoS). Simple linear regression analysis was used to estimate the number of future publications on this subject. RESULTS: A total of 4742 publications were found, 2552 (53.8%) of them were articles. Most of the articles were on subjects related to immunology (1274; 49.9%) and allergy (1229; 48.1%). Clinical and Experimental Allergy (222; 8.7%) was the journal with the most publications. The USA was the country that most contributed to the literature with 461 (18.1%) articles. The countries producing the most publications on this subject were developed countries. The most active author was W.R. Thomas (66; 2.5%). The most productive institution was the University of Western Australia (91; 3.6%). The most cited article was published in the New England Journal of Medicine. CONCLUSION: According to the findings, developed countries were the most productive in publishing on house dust mites. By planning multinational research rather than regional studies, it may be suggested that researchers in underdeveloped or developing countries could also conduct more research on this subject.

Molecular detection of zoonotic bartonellae (B. henselae, B. elizabethae and B. rochalimae) in fleas collected from dogs in Israel.

Fleas represent an acknowledged burden on dogs worldwide. The characterization of flea species infesting kennel dogs from two localities in Israel (Rehovot and Jerusalem) and their molecular screening for Bartonella species (Rhizobiales: Bartonellaceae) was investigated. A total of 355 fleas were collected from 107 dogs. The fleas were morphologically classified and molecularly screened targeting the Bartonella 16S-23S internal transcribed spacer (ITS). Of the 107 dogs examined, 80 (74.8%) were infested with Ctenocephalides canis (Siphonaptera: Pulicidae), 68 (63.6%) with Ctenocephalides felis, 15 (14.0%) with Pulex irritans (Siphonaptera: Pulicidae) and one (0.9%) with Xenopsylla cheopis (Siphonaptera: Pulicidae). Fleas were grouped into 166 pools (one to nine fleas per pool) according to species and host. Thirteen of the 166 flea pools (7.8%) were found to be positive for Bartonella DNA. Detected ITS sequences were 99-100% similar to those of four Bartonella species: Bartonella henselae (six pools); Bartonella elizabethae (five pools); Bartonella rochalimae (one pool), and Bartonella bovis (one pool). The present study indicates the occurrence of a variety of flea species in dogs in Israel; these flea species are, in turn, carriers of several zoonotic Bartonella species. Physicians, veterinarians and public health workers should be aware of the presence of these pathogens in dog fleas in Israel and preventive measures should be implemented.

Molecular detection of Rickettsia aeschlimannii in Hyalomma spp. ticks from camels (Camelus dromedarius) in Nigeria, West Africa.

Several species of the spotted fever group rickettsiae have been identified as emerging pathogens throughout the world, including in Africa. In this study, 197 Hyalomma ticks (Ixodida: Ixodidae) collected from 51 camels (Camelus dromedarius) in Kano, northern Nigeria, were screened by amplification and sequencing of the citrate synthase (gltA), outer membrane protein A (ompA) and 17-kDa antigen gene fragments. Rickettsia sp. gltA fragments were detected in 43.3% (42/97) of the tick pools tested. Rickettsial ompA gene fragments (189 bp and 630 bp) were detected in 64.3% (n = 27) and 23.8% (n = 10) of the gltA-positive tick pools by real-time and conventional polymerase chain reaction (PCR), respectively. The amplicons were 99-100% identical to Rickettsia aeschlimannii TR/Orkun-H and R. aeschlimannii strain EgyRickHimp-El-Arish in GenBank. Furthermore, 17-kDa antigen gene fragments of 214 bp and 265 bp were detected in 59.5% (n = 25) and 38.1% (n = 16), respectively, of tick pools, and sequences were identical to one another and 99-100% identical to those of the R. aeschlimannii strain Ibadan A1 in GenBank. None of the Hyalomma impressum ticks collected were positive for Rickettsia sp. DNA. Rickettsia sp. gltA fragments (133 bp) were detected in 18.8% of camel blood samples, but all samples were negative for the other genes targeted. This is the first report to describe the molecular detection of R. aeschlimannii in Hyalomma spp. ticks from camels in Nigeria.

Ectoparasites in urban stray cats in Jerusalem, Israel: differences in infestation patterns of fleas, ticks and permanent ectoparasites.

In a period cross-sectional study performed to examine ectoparasites on 340 stray cats in Jerusalem, Israel, 186 (54.7%) were infested with the cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae), 49 (14.4%) with the cat louse, Felicola subrostratus (Phthiraptera: Trichodectidae), 41 (12.0%) with the ear mite, Otodectes cynotis (Astigmata: Psoroptidae), three (0.9%) with the fur mite, Cheyletiella blakei (Trobidiformes: Cheyletidae), two (0.6%) with the itch mite Notoedres cati (Astigmata: Sarcoptidae), and 25 (7.3%) with ticks of the species Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae), Rhipicephalus turanicus or Haemaphysalis adleri (Ixodida: Ixodidae). A higher number of flea infestations was observed in apparently sick cats (P < 0.05) and in cats aged < 6 months (P < 0.05). The proportion of flea-infested cats (P < 0.01), as well as the number of fleas per infested cat (P < 0.01), was higher in autumn than in other seasons. By contrast with findings in cats with flea infestations, rates of infestation with ticks were higher amongst cats with clinical signs (P < 0.01) and cats aged ≥ 6 months (P < 0.05). The high rates of ectoparasite infestation in the cats studied constitute a risk for the spread of vector-borne infections of zoonotic and veterinary importance.

Pain related to maggot debridement therapy.

OBJECTIVE: To summarise our experience with maggot debridement therapy (MDT) in relation to pain observed in patients treated in 16 departments and units of the Hadassah Hospital in Jerusalem, Israel. METHOD: A secondary analysis of data from 435 patients. Maggots were either placed directly on the wound using a cage-like dressing (DA), or they were applied to the wound encased in a previously prepared hermetic tea-bag like pouch (TBA). During each treatment, patients were asked whether they felt any difference in the level of pain before and during MDT treatment. RESULTS: Overall, 165 patients (38%) reported increased pain during MDT. Seventeen patients (41%), who were treated with the TBA technique, and 148 patients (38%), who were treated with the DA technique, reported increased pain and were treated with analgesics before or during MDT. In five patients, the treatment had to be discontinued due to uncontrolled pain during MDT. Pain control measures were undertaken in patients who were already in intense pain prior to the initiation of MDT and in those patients who reported intense pain during DA treatment. The measures included shorter periods of application of maggots, use of the TBA rather than DA technique, and applying relatively small maggots as well as a smaller number of maggots during an MDT session. In patients who continued reporting intense pain, systemic analgesic medications and peripheral nerve blocks were used. CONCLUSION: Since a full debridement requires an average of 2-3 maggot cycles, which last 3-5 days, and since a large percentage of patients treated with MDT complain of pain that may last throughout the therapy period, it is deemed worthwhile and even essential to titrate analgesics as needed and be prepared to treat patients even with potent analgesics, such as opioids. In cases when pain is intense and uncontrolled with systemic medications, peripheral nerve blocks should be considered. DECLARATION OF INTEREST: There were no external sources of funding for this study. The authors have no conflicts of interest to declare.

The use of maggot debridement therapy in the treatment of chronic wounds in hospitalised and ambulatory patients.

OBJECTIVE: To summarise our experience of the use of medicinal maggots for the debridement of necrotic chronic wounds and to try and identify prognostic factors for debridement success and associated pain. METHOD: During the years 1996­2009, 723 wounds of 435 patients (180 females and 255 males) were treated with maggot debridement therapy (MDT) in 16 departments and units of the Hadassah Hospital in Jerusalem, Israel. Overall, 261 patients were treated during hospitalisation, while 174 were treated as ambulatory patients. In 90.5% of the patients the wounds were located on the leg, but only 48.0% had diabetic foot ulcers. The wound duration range from one to 240 months (mean=8.9; median=4 months). Sterile maggots of the green bottle fly, Lucilia sericata, were used for MDT. In 90.6% of the cases, maggots were placed directly on the wound using a cage-like dressing and left for 24 hours, while in 9.4% of the patients maggots concealed in a tea-bag like polyvinyl netting were used. The concealed maggots were left on the wound for 2­3 days. RESULTS: The number of treatments was 1­48 (mean=2.98; median=2) and the duration of the treatment varied between one and 81 days (mean=4.65; median=3). In 357 patients (82.1%) complete debridement of the wound was achieved, while in 73 patients (16.8%) the debridement was partial and in five (1.1%) it was ineffective. Increased pain or discomfort during MDT were reported in 38% of the patients. CONCLUSION: MDT is a very safe, simple and effective treatment modality for chronic wounds in ambulatory and hospitalised patients. DECLARATION OF INTEREST: There were no external sources of funding for this study. The authors have no additional conflicts of interest to declare.

Crossbreeding between different geographical populations of the brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae).

Brown dog ticks are distributed world-wide, and their systematics and phylogeny are the subject of an ongoing debate. The present study evaluates the reproductive compatibility between Rhipicephalus sanguineus ticks from North America, Israel, and Africa. Female ticks of the parent generation were mated with males from the same and alternate colonies. Every pure and hybrid cohort was maintained separately into the F2 generation with F1 females being allowed to mate only with males from the same cohort. The following survival parameters were measured and recorded for every developmental stage: feeding duration and success; engorgement weight, fertility, and fecundity of females; molting and hatching success. Ticks from North American and Mediterranean populations hybridized successfully. The survival parameters of all their hybrid lines were similar to those in pure lines throughout the F1 generation, and F1 adults were fully fertile. Parent adult ticks from the African population hybridized with either North American or Mediterranean ticks and produced viable progenies whose survival parameters were also similar to those in pure lines throughout the F1 generation. However, F1 adults in the four hybrid lines that included African ancestry were infertile. No parthenogenesis was observed in any pure or hybrid lines as proportion of males in F1 generation ranged from 40 to 60 %. Phylogenetic analysis of the 12S rDNA gene sequences placed African ticks into a separate clade from those of the North American or Mediterranean origins. Our results demonstrate that Rh. sanguineus ticks from North America and Israel represent the same species, whereas the African population used in this study is significantly distant and probably represents a different taxon.

Effects of blood type and blood handling on feeding success, longevity and egg production in the body louse, Pediculus humanus humanus.

The effects of feeding different types of human blood to human body lice, Pediculus humanus humanus L. (Phthiraptera: Pediculidae), on feeding success, longevity and numbers of eggs laid were investigated using an artificial blood-feeding system in the laboratory. No significant differences were found between lice fed on different human blood types for any of the parameters tested. However, when lice were fed on human blood of one blood type followed immediately by a different blood type, they took significantly smaller bloodmeals, their longevity was reduced and they laid fewer eggs per female than control lice that had been fed twice on the same human blood type. When lice were fed human blood that had been stored for 1-26 weeks, the quantity of blood taken, the proportion of lice that became fully engorged and lice longevity diminished gradually as the storage time of the blood increased, but there was no effect of storage time on the mean number of eggs laid per female. However, lice would not feed on 26-week-old blood. The type of anticoagulant used had a significant effect on the proportion fed, longevity and number of eggs laid per female. Generally, EDTA (ethylenediaminetetraacetic acid)-treated blood reduced longevity and the number of eggs laid per female to a greater degree than heparinized or citrated blood. Lice fed on rabbit blood took significantly larger amounts of blood, lived longer and laid a higher mean number of eggs per female than lice fed on human blood.

Co-feeding as a route for transmission of Rickettsia conorii israelensis between Rhipicephalus sanguineus ticks.

Rickettsia conorii is widely distributed in Europe, Asia, and Africa. The brown dog tick, Rhipicephalus sanguineus, is the recognized vector of R. conorii. In this study, we assessed the efficiency of R. conorii israelensis transmission between co-feeding Rh. sanguineus ticks. Infected Rh. sanguineus adults and uninfected nymphs were fed simultaneously upon either naïve dogs or a dog previously exposed to this agent. When ticks were placed upon naïve dogs, 92-100% of nymphs acquired the infection and 80-88% of infected engorged nymphs transmitted it transstadially. When ticks were placed upon a seropositive dog, only 8-28.5% of recipient nymphs became infected. Our results establish the first evidence for efficient natural transmission of R. conorii israelensis between co-feeding ticks upon both naïve and seropositive dogs. This route of transmission can ensure continuous circulation of R. conorii israelensis in tick vectors even in the absence of naïve reservoir hosts.

Incongruent effects of two isolates of Rickettsia conorii on the survival of Rhipicephalus sanguineus ticks.

Rickettsia conorii, the etiologic agent of Mediterranean spotted fever is widely distributed in Southern Europe, the Middle East, Africa, India and the Caspian region. In the Mediterranean region, the brown dog tick, Rhipicephalus sanguineus, is the recognized vector of R. conorii. To study tick-pathogen relationships and pathogenesis of infection caused in model animals by the bite of an infected tick, we attempted to establish a laboratory colony of Rh. sanguineus persistently infected with R. conorii. Rhipicephalus sanguineus ticks of North American and Mediterranean origin were exposed to R. conorii isolates of African (R. conorii conorii strain Malish) and Mediterranean (R. conorii israelensis strain ISTT) origin. Feeding of ticks upon infected mice and dogs, intra-hemocoel inoculation, and submersion in suspensions of purified rickettsiae were used to introduce the pathogen into uninfected ticks. Feeding success, molting success and the longevity of molted ticks were measured to assess the effects of R. conorii on the survival of Rh. sanguineus. In concordance with previously published results, Rh. sanguineus larvae and nymphs from both North American and Mediterranean colonies exposed to R. conorii conorii Malish experienced high mortality during feeding and molting or immediately after. The prevalence of infection in surviving ticks did not exceed 5%. On the other hand, exposure to ISTT strain had lesser effect on tick survival and resulted in 35-66% prevalence of infection. Rh. sanguineus of Mediterranean origin were more susceptible to infection with either strain of R. conorii than those from North America. Previous experimental studies had demonstrated transovarial and transstadial transmission of R. conorii in Rh. sanguineus; however, our data suggest that different strains of R. conorii may employ different means of maintenance in nature. The vertebrate host may be a more important reservoir than previously thought, or co-feeding transmission between different generations of ticks may obviate or lessen the requirement for transovarial maintenance of R. conorii.

Treatment of scabies infestations.

Scabies is an intensely pruritic disorder induced by an immune allergic response to infestation of the skin by the mite Sarcoptes scabiei. The biology of the mite, the clinical aspects and diagnosis of scabies infestations as well as the treatment of choice with 5% permethrin dermal cream and the use of scabicides based on other chemical substances are reviewed.

Overview and features of larval developmental sites of biting midges species associated with livestock in Israel with implications to their control.

The larval developmental sites of Culicoides species were assessed from 1155 samples collected during the years 1969-2003. Culicoides circumscriptus was most prolific in mud with medium organic matter with proportional representation of 55.8%. Culicoides imicola breeds mainly in damp mixture of rotten, decomposed animal dung with or without some mud, with proportional representation of 97.2%. Culicoides obsoletus was found mostly in rotten banana stumps, with proportional representation of almost 100%. Culicoides puncticollis was found in mud with a medium amount of organic matter with proportional representation of 35.6%. Culicoides distinctipennis showed 22.2% proportional representation for mud poor in organic matter. Culicoides schultzei gr. was most prolifically in mud rich in organic matter with proportional representation of 6.2%. Culicoides cataneii was most prolifically in mud with a medium amount of organic matter with proportional representation of 1.8%. Maximum duration time to emergence from the larval developmental sites ranged from seven weeks in C. obsoletus to fourteen weeks in C. circumscriptus and nine weeks in C. imicola. All the studied species breed throughout the year. Significant innate differences in the proportions of the sexes were found in the emergence of six species.

Antibacterial properties of whole body extracts and haemolymph of Lucilia sericata maggots.

OBJECTIVE: To partially characterise maggot-secreted antibacterial substances and determine their range of activity against different bacteria. METHOD: Sterile and non-sterile maggots maintained in the laboratory and taken from chronic wounds of treated patients were used. Whole body extracts and haemolymph were fractionated and their range of activity against bacteria was tested using the zone of inhibition assay. The mode of action of bacterial destruction was examined by viable counts, influx of K+ and changes in the membrane potential by scanning electron microscope (SEM). RESULTS: Extracts of sterile and non-sterile maggots showed an activity of 200 arbitrary units (AU)/ml and 400AU/ml respectively. Maggots removed from chronic wounds had an activity of 1200AU/ml. Injuring sterile maggots with a sterile needle doubled the antibacterial activity within 24 hours, while the antibacterial activity of haemolymph increased fourfold after injury with a sterile needle and sixteenfold with an infected needle. The fractions with a molecular weight of < 1kDa and 3-10kDa showed antibacterial activity against Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa, Klebsiella pneumoniae and methicillin-resistant Staphylococcus aureus (MRSA) isolated from wounds. The fraction with a molecular weight of < 1kDa lysed over 90% of the bacteria within 15 minutes by causing an influx of K+ and changing the membrane potential of bacteria. CONCLUSION: The nature of the antibacterial materials extracted from maggots not only indicates their ability to ingest the necrotic tissue on the wound, but also their potential significance in wound healing,

Use of temperature and water immersion to control the human body louse (Anoplura: Pediculidae).

Physical methods such as high and low temperatures were used in the past for the control of human body louse, Pediculus humanus humanus L. (Anoplura: Pediculidae). In the current study, the minimum time necessary to kill all lice after exposing them to temperatures other than those described in the literature, the mortality of lice after immersing them in water, and the survival of lice whose legs were amputated were studied. All lice died after 6 d at 6 degrees C, after 11 d at 24 degrees C, and after 9 d at 31 degrees C. At -17 degrees C, all lice were dead after 35 min, whereas at -70 degrees C, all lice were dead after 1 min. All lice died after immersion in water within 19 h. The differences in mortality were significant but borderline between controls and lice whose two legs were amputated immediately or 24 h after feeding (3.3 versus 13.3% and 8.3 versus 21.7%). For lice whose leg was amputated 48 h after feeding, significant differences were found between controls and lice with one amputated leg (13.3 versus 48.3%), between controls and lice with two amputated legs (13.3 versus 68.3%), and between lice with one and two amputated legs (48.3 versus 68.3%).

Clinical applications for maggots in wound care.

Maggot debridement therapy (MDT) was first introduced in the US in 1931 and was routinely used there until mid-1940s in over 300 hospitals. With the advent of antibacterials, maggot therapy became rare until the early 1990s, when it was re-introduced first in the US, and later in Israel, the UK, Germany, Sweden, Switzerland, Ukraine and Thailand. Sterile maggots of the green bottle fly, Lucilia (Phaenicia) sericata, are used for MDT. Up to 1000 maggots are introduced in the wound and left for 1 to 3 days. MDT could be used for any kind of purulent, sloughy wound on the skin, independent of the underlying diseases or the location on the body for ambulatory as well as for hospitalized patients. One of the major advantages of MDT is that the maggots separate the necrotic tissue from the living tissue, making a surgical debridement easier. In 80 to 95% of the cases, a complete or significant debridement of the wound is achieved. As therapy progresses, new layers of healthy tissue are formed over the wounds. The offensive odor emanating from the necrotic tissue and the intense pain accompanying the wound decrease significantly. In a significant number of patients, an immediate amputation can be prevented as a result of MDT. In other cases, a more proximal amputation could be avoided. It is also possible that in patients with deep wounds, where septicemia is a serious threat, this can be prevented as a result of MDT. The majority of patients do not complain of any major discomfort during the treatment. Psychological and esthetic considerations are obvious. Maggots can occasionally cause a tickling or itching sensation. Approximately 20 to 25% of the patients with superficial, painful wounds, complain of increased pain during treatment with maggots, and are treated with analgesics. MDT has been proven to be an effective method for cleaning chronic wounds and initiating granulation. It is a simple, efficient, well tolerated and cost-effective tool for the treatment of wounds and ulcers, which do not respond to conventional treatment and surgical intervention.

Prevention and treatment of head lice in children.

Head louse infestations (pediculosis) are prevalent worldwide. In developed countries, the infestation rate of 4- to 13-year-old children remains high despite preventive efforts. This is due to the existence of numerous ineffective pediculicides, the incorrect use of the effective agents, toxicological concerns and the development of louse strains resistant to insecticides. One of the most effective tools for the prevention and control of lice is the louse comb, which should be used regularly for the detection of living lice at an early stage of infestation, and as an accessory to any treatment method to remove living and dead lice. The louse comb can also be used systematically for the treatment of infestations, for confirmation that treatment with pediculicides has been successful, and for the removal of nits (dead eggs or egg shells). Most pediculicides are only partially ovicidal. Therefore, 10 days after beginning treatment with any antilouse product, the scalp of the child should be examined. If no living lice are found, the treatment should be discontinued. If living lice are still present, treatment should be continued with a product containing a different active ingredient. Suffocating agents such as olive, soya, sunflower and corn oils, hair gels and mayonnaise are able to kill a significant number of lice only if they are applied in liberal quantities for more than 12 hours. However, they lubricate the hair and therefore may facilitate combing and removing lice and eggs from the scalp. Nits may remain glued on the hair for at least 6 months, even after a successful treatment, and lead to a false positive diagnosis of louse infestation. If nits are seen on the hair, the child should be examined, but treatment should be initiated only if living lice are found. Formulations containing 5% acetic acid or 8% formic acid, as well as acid shampoos (pH 4.5 to 5.5) and conditioners, in combination with a louse comb, can be helpful for removing nits. There is no conclusive evidence that using essential oils to repel lice is effective. Regular examination of the child's head using a louse comb is the best measure to detect re-infestation at an early stage. Educating caregivers, nurses and teachers about louse biology, epidemiology, prevention and control is of paramount importance. The psychological effect of an infestation with lice is significant and often associated with anxiety and fear. The child should not be made to feel responsible for having lice, or be punished or reprimanded.

Rhipicephalus sanguineus and R. turanicus (Acari:Ixodidae): closely related species with different biological characteristics.

Life cycle parameters of 2 closely related tick species, Rhipicephalus sanguineus Latreille and R. turanicus Pomerantsev, were studied under laboratory conditions. Both Rhipicephalus, which have small adults, demonstrated the same adaptations as large tick species inhabiting deserts and semideserts: high reproductive rate, decrease in egg size, and an increase in interstage growth to compensate for the smaller size at birth. Pronounced quantitative differences between both species were discerned in relation to these adaptations. Female R. turanicus produced twice as many eggs as R. sanguineus which was facilitated by the greater amount of blood engorged by females and by the smaller egg weight in R. turanicus as compared with R. sanguineus. In all developmental stages, the weight increase from unfed to fed ticks was greater in R. turanicus than in R. sanguineus (23% higher in larvae, 118% in nymphs, and 26% in females). The increase in weight in R. turanicus from the unfed larva (0.013 mg) to the unfed female (3.31 mg) was 254-fold, and in R. sanguineus it was 127-fold (from 0.021 to 2.54 mg). In nymphal R. turanicus, the higher density and the greater height of the dorsal epicuticular folds, as well as procuticular indentations found inside the folds allow this tick to stretch its alloscutum during blood engorgement to a greater extent than R. sanguineus. The rates of blood ingestion (for nymphs and females), egg maturation, and metamorphosis were 1.1-1.7 times greater in R. turanicus than in R. sanguineus. A life cycle strategy with both a higher reproductive rate and faster development in R turanicus may be explained by its greater dependence on environmental factors than that in R. sanguineus.

Systemic activity of ivermectin on the human body louse (Anoplura: Pediculidae).

Eighty-one to 100% of nymphs and females of the human body louse (Pediculus humanus humanus) that fed artificially on blood containing 2.5-10 ng ivermectin/ml died. The mortality of nymphs and female lice fed on rabbits treated with 200 micrograms/kg ivermectin was very high during the first two to three days, then declined sharply, reaching the level of the controls on day six. Nymphs were more sensitive than females. The average number of eggs laid by surviving females and the percentage that hatched from those eggs were lower than in controls.