Molecular detection and characterization of Bartonella spp. in small mammals in the Amazonia and Cerrado biomes, midwestern Brazil

Although Bartonella spp. have been worldwide described in rodents and bats, few studies have reported these agents in marsupials. The present work aimed to investigate the occurrence and genetic diversity of Bartonella in small mammals (rodents, marsupials, and bats) and associated ectoparasites in two ecoregions (Amazonia and Cerrado biomes) in midwestern Brazil. For this purpose, DNA samples from 378 specimens of small mammals (128 rodents, 111 marsupials, and 139 bats) and 41 fleas (Siphonaptera) were screened for the Bartonella genus employing a quantitative real-time PCR assay (qPCR) based on the nuoG (nicotinamide adenine dinucleotide dehydrogenase gamma subunit) gene. Then, positive samples in qPCR were submitted to conventional PCR (cPCR) assays targeting the gltA, ftsZ, and rpoB genes. One (0.78 %) rodent, 23 (16.54 %) bats, and 3 (7.31 %) fleas showed positive results in the qPCR for Bartonella sp. After cPCR amplification and sequencing, 13 partial Bartonella DNA sequences of the following genes were obtained only from bats´ blood samples: 9 gltA (citrate synthase), 3 ftsZ (cell division protein), and 1 rpoB (RNA polymerase beta subunit). The maximum likelihood inference based on the gltA gene positioned the obtained sequences in three different clades, closely related to Bartonella genotypes previously detected in other bat species and bat flies sampled in Brazil and other countries from Latin America. Similarly, the ftsZ sequences clustered in two different clades with sequences described in bats from Brazil, other countries from Latin America, and Georgia (eastern Europe). Finally, the Bartonella rpoB from a specimen of Lophostoma silvicolum clustered with a Bartonella sp. sequence obtained from a Noctilio albiventris (KP715475) from French Guiana. The present study provided valuable insights into the diversity of Bartonella genotypes infecting bats from two ecoregions (Amazonia and Cerrado) in midwestern Brazil and emphasized that further studies should be conducted regarding the description and evaluation of different lineages of Bartonella in wild small mammals and their ectoparasites in different Brazilian biomes.

Identification of tungiasis infection hotspots with a low-cost, high-throughput method for extracting Tunga penetrans (Siphonaptera) off-host stages from soil samples-An observational study

BACKGROUND

The sand flea, Tunga penetrans, is the cause of a severely neglected parasitic skin disease (tungiasis) in the tropics and has received little attention from entomologists to understand its transmission ecology. Like all fleas, T. penetrans has environmental off-host stages presenting a constant source of reinfection. We adapted the Berlese-Tullgren funnel method using heat from light bulbs to extract off-host stages from soil samples to identify the major development sites within rural households in Kenya and Uganda.

METHODS AND FINDINGS

Simple, low-cost units of multiple funnels were designed to allow the extraction of >60 soil samples in parallel. We calibrated the method by investigating the impact of different bulb wattage and extraction time on resulting abundance and quality of off-host stages. A cross-sectional field survey was conducted in 49 tungiasis affected households. A total of 238 soil samples from indoor and outdoor living spaces were collected and extracted. Associations between environmental factors, household member infection status and the presence and abundance of off-host stages in the soil samples were explored using generalized models. The impact of heat (bulb wattage) and time (hours) on the efficiency of extraction was demonstrated and, through a stepwise approach, standard operating conditions defined that consistently resulted in the recovery of 75% (95% CI 63-85%) of all present off-host stages from any given soil sample. To extract off-host stages alive, potentially for consecutive laboratory bioassays, a low wattage (15-25 W) and short extraction time (4 h) will be required. The odds of finding off-host stages in indoor samples were 3.7-fold higher than in outdoor samples (95% CI 1.8-7.7). For every one larva outdoors, four (95% CI 1.3-12.7) larvae were found indoors. We collected 67% of all off-host specimen from indoor sleeping locations and the presence of off-host stages in these locations was strongly associated with an infected person sleeping in the room (OR 10.5 95% CI 3.6-28.4).

CONCLUSION

The indoor sleeping areas are the transmission hotspots for tungiasis in rural homes in Kenya and Uganda and can be targeted for disease control and prevention measures. The soil extraction methods can be used as a simple tool for monitoring direct impact of such interventions.

Molecular detection and identification of hemotropic Mycoplasma species in dogs and their ectoparasites in Iran

Hemotropic Mycoplasma species are vector-borne bacteria that attach and grow on the surface of erythrocytes in various mammals, yet reports of canine hemoplasmosis in Iran are scarce. The aim of this study was molecular detection and identification of hemoplasmas in the blood of dogs (n = 370) from five provinces of Iran and ectoparasites infesting them including Ctenocephalides canis and Pulex irritans fleas, Rhipicephalus sanguineus sensu lato ticks, Heterodoxus spiniger lice and Hippobosca longipennis keds. Hemotropic Mycoplasma spp. pathogens were detected using genus-specific conventional PCRs, and subsequently identified using species-specific PCRs for Mycoplasma haemocanis (Mhc), and Candidatus Mycoplasma haematoparvum (CMhp). Sanger sequencing was then performed to confirm the species. Correlation of infection and risk factors (geographical area, keeping condition, body condition, sex, age, ectoparasite infestation) were analyzed. In total, 210 dogs (56.7%) were tested PCR-positive for hemotropic Mycoplasma spp. Species-specific PCR and sequencing revealed infection with Mhc in 17.8%, with CMhp in 7.02% and co-infection in 31.9% of dogs. Flea infestation, poor body condition, and being older than 3-years-old correlated with hemoplasmosis. In ectoparasites, DNA of hemoplasmas were detected only in fleas i.e. Mhc in P. irritans, CMhp in P. irritans and C. canis, and co-infection in C. canis. To our knowledge, this is the first large-scale molecular epidemiology study of canine hemoplasmosis in Iran. Considering the high prevalence of canine hemoplasmosis all over the country including potentially zoonotic CMhp, effective ectoparasite control strategies, regular examination of dogs, successful chemoprophylaxis and public awareness strategies are advocated.

Studies on the Determination of Ectoparasites and the Prevalence Rate in Cattle in İzmir, Aydın and Muğla Regions

Objective

The aim of the study is to determine the prevalence rates of ectoparasites (external parasites) seen in cattle in Muğla, Aydın and İzmir regions.

Methods

For ectoparasite screening, a total of 1,353 cattle breeds from Muğla, Aydın and İzmir regions were included in the study. Ectoparasite samples were collected with the help of hand, forceps, comb and scalpel, brought to the laboratory in plastic containers containing 70% alcohol and examined under a microscope.

Results

In the study, 191 (14.12%) of 1,353 cattle were infested with external parasites. Of the cattle, 138 (72.25%) ticks, 24 (12.57%) lice, 9 (4.71%) tabanid, 8 (4.19%) hippoboscid, 7 (3.66%) fleas and 5 (2.62%) mites were detected. Accordingly, 4 tick species in cattle Hyalomma marginatum, Hyalomma excavatum, Hyalomma detritum, Rhipicephalus turanicus, 4 lice species (Bovicola bovis, Linognathus vituli, Solenopotes capillatus, Haematopinus quadripertusus ), 1 mite species (Chorioptes bovis), 2 flea species (Ctenocephalides canis, Ctenocephalides felis), 1 hippoboscid fly species (Hippobosca equina) ve 3 tabanid fly species (Tabanus bromius, Tabanus exclusus, Philipomyia aprica) diagnosed.

Conclusion

The presence of external parasites varied depending on the frequency of antiparasitic use in cattle.

The Parasites of Cats in Türkiye

Cats have an important and different place due to their close relationships with humans. Since most of the parasites they carry are zoonotic, it is important to detect them. According to the research, Dipylidium caninum, Joyeuxiella pasqualei, Toxocara spp., Toxascaris leonina, Giardia spp., Isospora spp., and Toxoplasma sp. were found to be higher in cats compared to other parasites. It has been determined that scabies and flea infestations are common as ectoparasites. This review aims to present the reported parasites and their prevalence rates in cats in Türkiye.

Ecological factors shaping the ectoparasite community assembly of the Azara's Grass Mouse, Akodon azarae (Rodentia: Cricetidae)

Parasites are integral members of the global biodiversity. They are useful indicators of environmental stress, food web structure and diversity. Ectoparasites have the potential to transmit vector-borne diseases of public health and veterinary importance and to play an important role in the regulation and evolution of host populations. The interlinkages between hosts, parasites and the environment are complex and challenging to study, leading to controversial results. Most previous studies have been focused on one or two parasite groups, while hosts are often co-infected by different taxa. The present study aims to assess the influence of environmental and host traits on the entire ectoparasite community composition of the rodent Akodon azarae. A total of 278 rodents were examined and mites (Mesostigmata), lice (Phthiraptera), ticks (Ixodida) and fleas (Siphonaptera) were determined. A multi-correspondence analysis was performed in order to analyze interactions within the ectoparasite community and the influence of environmental and host variables on this assembly. We found that environmental variables have a stronger influence on the composition of the ectoparasite community of A. azarae than the host variables analyzed. Minimum temperature was the most influential variable among the studied. In addition, we found evidence of agonistic and antagonistic interactions between ticks and mites, lice and fleas. The present study supports the hypothesis that minimum temperature plays a major role in the dynamics that shape the ectoparasite community of A. azarae, probably through both direct and indirect processes. This finding becomes particularly relevant in a climate change scenario.

Patterns and drivers of vector-borne microparasites in a classic metapopulation

Many organisms live in fragmented populations, which has profound consequences on the dynamics of associated parasites. Metapopulation theory offers a canonical framework for predicting the effects of fragmentation on spatiotemporal host–parasite dynamics. However, empirical studies of parasites in classical metapopulations remain rare, particularly for vector-borne parasites. Here, we quantify spatiotemporal patterns and possible drivers of infection probability for several ectoparasites (fleas, Ixodes trianguliceps and Ixodes ricinus) and vector-borne microparasites (Babesia microti, Bartonella spp., Hepatozoon spp.) in a classically functioning metapopulation of water vole hosts. Results suggest that the relative importance of vector or host dynamics on microparasite infection probabilities is related to parasite life-histories. Bartonella, a microparasite with a fast life-history, was positively associated with both host and vector abundances at several spatial and temporal scales. In contrast, B. microti, a tick-borne parasite with a slow life-history, was only associated with vector dynamics. Further, we provide evidence that life-history shaped parasite dynamics, including occupancy and colonization rates, in the metapopulation. Lastly, our findings were consistent with the hypothesis that landscape connectivity was determined by distance-based dispersal of the focal hosts. We provide essential empirical evidence that contributes to the development of a comprehensive theory of metapopulation processes of vector-borne parasites.

Knockdown resistance mutations are common and widely distributed in Xenopsylla cheopis fleas that transmit plague in Madagascar

BACKGROUND

Plague, caused by the bacterium Yersinia pestis, remains an important disease in Madagascar, where the oriental rat flea, Xenopsylla cheopis, is a primary vector. To control fleas, synthetic pyrethroids (SPs) have been used for >20 years, resulting in resistance in many X. cheopis populations. The most common mechanisms of SP resistance are target site mutations in the voltage-gated sodium channel (VGSC) gene.

METHODOLOGY/PRINCIPAL FINDINGS

We obtained 25 collections of X. cheopis from 22 locations across Madagascar and performed phenotypic tests to determine resistance to deltamethrin, permethrin, and/or dichlorodiphenyltrichloroethane (DDT). Most populations were resistant to all these insecticides. We sequenced a 535 bp segment of the VGSC gene and identified two different mutations encoding distinct substitutions at amino acid position 1014, which is associated with knockdown resistance (kdr) to SPs in insects. Kdr mutation L1014F occurred in all 25 collections; a rarer mutation, L1014H, was found in 12 collections. There was a significant positive relationship between the frequency of kdr alleles and the proportion of individuals surviving exposure to deltamethrin. Phylogenetic comparisons of 12 VGSC alleles in Madagascar suggested resistant alleles arose from susceptible lineages at least three times. Because genotype can reasonably predict resistance phenotype, we developed a TaqMan PCR assay for the rapid detection of kdr resistance alleles.

CONCLUSIONS/SIGNIFICANCE

Our study provides new insights into VGSC mutations in Malagasy populations of X. cheopis and is the first to report a positive correlation between VGSC genotypes and SP resistance phenotypes in fleas. Widespread occurrence of these two SP resistance mutations in X. cheopis populations in Madagascar reduces the viability of these insecticides for flea control. However, the TaqMan assay described here facilitates rapid detection of kdr mutations to inform when use of these insecticides is still warranted to reduce transmission of plague.

Serological evidence of Yersinia pestis infection in rodents and carnivores in Northwestern Iran

BACKGROUND

Plague may recur after several decades in its endemic regions; therefore, the continuous monitoring of wildlife is essential, even when no human cases are reported in the old foci. The present study was conducted to monitor rodents and their ectoparasites as well as carnivores to learn about the epidemiology of plague infection in an old focus of Iran.

METHODOLOGY

The present study was conducted from 2019 to 2020 in Takestan county of Qazvin Province in northwestern Iran. Rodents were caught using live traps, and their fleas were separated. Blood and spleen specimens were taken from the captured rodents. Serum samples were also collected from sheepdogs and wild carnivores. The collected samples were tested by culture, serology (ELISA), and molecular methods to detect Yersinia pestis infection.

FINDINGS

A total of 399 small mammals were caught, of which 68.6% were Meriones persicus. A total of 2438 fleas were collected from the rodents, 95.3% of which were Xenopsylla buxtoni. Overall, 23 out of 377 tested rodents (5.7%, CI 95%, 3.9-9.0) had IgG antibodies against the F1 antigen of Y. pestis, and all the positive samples belonged to M. persicus. Nine (4.8%) out of 186 collected sera from the sheepdogs' serum and one serum from the Canis aureus had specific IgG antibodies against the F1 antigen of Y. pestis. There were no positive cases of Y. pestis in the rodents and fleas based on the culture and real-time PCR.

CONCLUSION

Serological evidence of Y. pestis circulation was observed in rodents and carnivores (sheepdogs and C. aureus). The presence of potential plague vectors and serological evidence of Y. pestis infection in the surveyed animals could probably raise the risk of infection and clinical cases of plague in the studied region. Training health personnel is therefore essential to encourage their detection of possible human cases of the disease.

The role of cofeeding arthropods in the transmission of Rickettsia felis

Rickettsia felis is an emerging etiological agent of rickettsioses worldwide. The cosmopolitan cat flea (Ctenocephalides felis) is the primary vector of R. felis, but R. felis has also been reported in other species of hematophagous arthropods including ticks and mosquitoes. Canines can serve as a bacteremic host to infect fleas under laboratory conditions, yet isolation of R. felis from the blood of a vertebrate host in nature has not been realized. Cofeeding transmission is an efficient mechanism for transmitting rickettsiae between infected and uninfected fleas; however, the mechanism of transmission among different orders and classes of arthropods is not known. The potential for R. felis transmission between infected fleas and tick (Dermacentor variabilis) and mosquito (Anopheles quadrimaculatus) hosts was examined via cofeeding bioassays. Donor cat fleas infected with R. felis transmitted the agent to naïve D. variabilis nymphs via cofeeding on a rat host. Subsequent transstadial transmission of R. felis from the engorged nymphs to the adult ticks was observed with reduced prevalence in adult ticks. Using an artificial host system, An. quadrimaculatus exposed to a R. felis-infected blood meal acquired rickettsiae and maintained infection over 12 days post-exposure (dpe). Similar to ticks, mosquitoes were able to acquire R. felis while cofeeding with infected cat fleas on rats infection persisting in the mosquito for up to 3 dpe. The results indicate R. felis-infected cat fleas can transmit rickettsiae to both ticks and mosquitoes via cofeeding on a vertebrate host, thus providing a potential avenue for the diversity of R. felis-infected arthropods in nature.

Primarily associated with the common cat flea, Rickettsia felis is an intracellular bacterial pathogen that can be transmitted from the flea to vertebrate hosts. This flea-borne infection has now been identified worldwide as a human pathogen. In addition to fleas, other blood feeding arthropods including ticks and mosquitoes are being recognized as possible vectors of R. felis. Although the mammalian infectious source for arthropods is still unknown, cofeeding transmission of Rickettsia is known to occur between vectors of the same species. However, potential for flea transmission of R. felis to other orders and classes of arthropods is unknown. Here, we examined the potential for fleas to transmit R. felis to American dog ticks and mosquitoes during feeding events on rat hosts. Our data suggested that ticks and mosquitoes can be infected when simultaneously feeding on a host with R. felis-infected cat fleas.

Host species and environment drivers of ectoparasite community of rodents in a Mojave Desert wetlands

Drivers of patterns of ectoparasitism in rodents in patchy Mojave Desert wetlands were investigated. A total of 1,571 ectoparasites in Mesostigmata, Trombidiformes, Siphonaptera and Ixodida were collected from 341 rodents (Microtus californicus scirpensis, Mus musculus, Reithrodontomys megalotis, Peromyscus eremicus, and Neotoma lepida) at eleven marshes. Trombiculids accounted for 82.5% of mites, followed by the mesostigmatid Ornithonyssus bacoti (17.5%), with chiggers predominating on voles and harvest mice. There were at least three genera of chiggers (Eutrombicula alfreddugesi, Euschoengastia sp. novel, and Blankaartia sp. novel). Fleas included Orchopeas leucopus (90.3% of all fleas) and O. sexdentatus (9.7%), and ticks were the novel endemic Ixodes mojavensis (82.1% of ticks) and Dermacentor similis (17.9%). On all hosts and at all marshes, coverage-based rarefaction sampling was over 96%, indicating coverage sufficient for analysis. Dissimilarities in ectoparasite community structure were driven mainly by chiggers, I. mojavensis and O. leucopus. Northern marshes were dominated by chiggers; central marshes by I. mojavensis; and southern marshes by O. leucopus. Primary determinants of ectoparasite community structure were host species, patch size, and parasite interspecific interactions. Host species richness and environmental factors such as patch distance and water and plant availability were not significantly associated with patterns of ectoparasitism. There were nine (60%) significant negative pairwise associations between ectoparasite taxa and no significant positive relationships. Ixodes mojavensis had the highest number of negative associations (with five other species), followed by chiggers and O. bacoti with two negative associations each. The study area is among the most arid in North America and supports numerous rare and endemic species in increasingly isolated wetland habitat patches; knowledge of ectoparasite ecology in this region identifies potential ectoparasite vectors, and provides information needed to design and implement programs to manage vector-borne diseases for purposes of wildlife conservation.

The changing triad of plague in Uganda: invasive black rats (Rattus rattus), indigenous small mammals, and their fleas

Rattus rattus was first reported from the West Nile Region of Uganda in 1961, an event that preceded the appearance of the first documented human plague outbreak in 1970. We investigated how invasive R. rattus and native small mammal populations, as well as their fleas, have changed in recent decades. Over an 18-month period, a total of 2,959 small mammals were captured, sampled, and examined for fleas, resulting in the identification of 20 small mammal taxa that were hosts to 5,109 fleas (nine species). Over three-fourths (75.8%) of captured mammals belonged to four taxa: R. rattus, which predominated inside huts, and Arvicanthis niloticus, Mastomys sp., and Crocidura sp., which were more common outside huts. These mammals were hosts for 85.8% of fleas collected, including the efficient plague vectors Xenopsylla cheopis and X. brasiliensis, as well as likely enzootic vectors, Dinopsyllus lypusus and Ctenophthalmus bacopus. Flea loads on small mammals were higher in certain environments in villages with a recent history of plague compared to those that lacked such a history. The significance of these results is discussed in relation to historical data, the initial spread of plague in the WNR and the continuing threat posed by the disease.

Zoonotic Bacteria in Fleas Parasitizing Common Voles, Northwestern Spain

We detected Francisella tularensis and Bartonella spp. in fleas parasitizing common voles (Microtus arvalis) from northwestern Spain; mean prevalence was 6.1% for F. tularensis and 51% for Bartonella spp. Contrasted vector–host associations in the prevalence of these bacteria suggest that fleas have distinct roles in the transmission cycle of each pathogen in nature.

Identification of Bartonella rochalimae in Guinea Pigs (Cavia porcellus) and Fleas Collected from Rural Peruvian Households

In the present study, we tested 391 fleas collected from guinea pigs (Cavia porcellus) (241 Pulex species, 110 Ctenocephalides felis, and 40 Tiamastus cavicola) and 194 fleas collected from human bedding and clothing (142 Pulex species, 43 C. felis, five T. cavicola, and four Ctenocephalides canis) for the presence of Bartonella DNA. We also tested 83 blood spots collected on Flinders Technology Associates (FTA) cards from guinea pigs inhabiting 338 Peruvian households. Bartonella DNA was detected in 81 (20.7%) of 391 guinea pig fleas, in five (2.6%) of 194 human fleas, and in 16 (19.3%) of 83 guinea pig blood spots. Among identified Bartonella species, B. rochalimae was the most prevalent in fleas (89.5%) and the only species found in the blood spots from guinea pigs. Other Bartonella species detected in fleas included B. henselae (3.5%), B. clarridgeiae (2.3%), and an undescribed Bartonella species (4.7%). Our results demonstrated a high prevalence of zoonotic B. rochalimae in households in rural areas where the research was conducted and suggested a potential role of guinea pigs as a reservoir of this bacterium.

From endosymbionts to host communities: factors determining the reproductive success of arthropod vectors

Elucidating the factors determining reproductive success has challenged scientists since Darwin, but the exact pathways that shape the evolution of life history traits by connecting extrinsic (e.g., landscape structure) and intrinsic (e.g., female's age and endosymbionts) factors and reproductive success have rarely been studied. Here we collected female fleas from wild rodents in plots differing in their densities and proportions of the most dominant rodent species. We then combined path analysis and model selection approaches to explore the network of effects, ranging from micro to macroscales, determining the reproductive success of these fleas. Our results suggest that female reproductive success is directly and positively associated with their infection by Mycoplasma bacteria and their own body mass, and with the rodent species size and total density. In addition, we found evidence for indirect effects of rodent sex and rodent community diversity on female reproductive success. These results highlight the importance of exploring interrelated factors across organization scales while studying the reproductive success of wild organisms, and they have implications for the control of vector-borne diseases.

Contribution of land use to rodent flea load distribution in the plague endemic area of Lushoto District, Tanzania

Fleas associated with different rodent species are considered as the major vectors of bubonic plague, which is still rampant in different parts of the world. The objective of this study was to investigate the contribution of land use to rodent flea load distribution at fine scale in the plague endemic area of north-eastern Tanzania. Data was collected in three case areas namely, Shume, Lukozi and Mwangoi, differing in plague incidence levels. Data collection was carried out during both wet and dry seasons of 2012. Analysis of Variance and Boosted Regression Tree (BRT) statistical methods were used to clarify the relationships between fleas and specific land use characteristics. There was a significant variation (P ≤ 0.05) of flea indices in different land use types. Fallow and natural forest had higher flea indices whereas plantation forest mono-crop and mixed annual crops had the lowest flea indices among the aggregated land use types. The influence of individual land use types on flea indices was variable with fallow having a positive effect and land tillage showing a negative effect. The results also demonstrated a seasonal effect, part of which can be attributed to different land use practices such as application of pesticides, or the presence of grass strips around fields. These findings suggest that land use factors have a major influence on rodent flea abundance which can be taken as a proxy for plague infection risk. The results further point to the need for a comprehensive package that includes land tillage and crop type considerations on one hand and the associated human activities on the other, in planning and implementation of plague control interventions.

CORRELATION OF HOST SPECIFICITY, ENVIRONMENTAL FACTORS AND ORIENTAL RAT FLEA ABUNDANCE

Fleas are the vectors of many communicable diseases that are normally found in oriental rats. Climate and environmental changes influence the habitat and migration patterns of vectors. In this study, the oriental rat flea abundance, represented as total flea index, was determined in correlation to host specificity and various environmental factors. The number of hosts and fleas calculated from 3 specific habitats (shipping area, decayed area, and market area) from July 2010 to June 2011. The results showed that the common hosts in the shipping area and decayed area were Rattus rattus and R. exulans, with the total flea indexes of 3.36 and 1.58. R. norvegicus was the most common host identified in the market area. Fleas were virtually absent in rat hosts collected from the market area. Both the density of reservoir hosts and the total flea index were positively correlated with the mean annual rainfall and temperature. These data could be useful for control of rat populations in each specific habitat.

Bartonella infection in rodents and their flea ectoparasites: an overview

Epidemiological studies worldwide have reported a high prevalence and a great diversity of Bartonella species, both in rodents and their flea parasites. The interaction among Bartonella, wild rodents, and fleas reflects a high degree of adaptation among these organisms. Vertical and horizontal efficient Bartonella transmission pathways within flea communities and from fleas to rodents have been documented in competence studies, suggesting that fleas are key players in the transmission of Bartonella to rodents. Exploration of the ecological traits of rodents and their fleas may shed light on the mechanisms used by bartonellae to become established in these organisms. The present review explores the interrelations within the Bartonella-rodent-flea system. The role of the latter two components is emphasized.

[Fleas notified on Microtus fuscus foci in Sichuan province]

OBJECTIVE

To analyzed the variant information on the indices regarding fleas from natural foci of Microtus plague in Sichuan epidemic area during 2000 to 2008.

METHODS

Statistical and analytical methods were used on the surveillance data regarding Microtus fuscus plague.

RESULTS

There were 19 flea species identified and the share of Callopsylla sparsity was 62.79 percent while the share of Amphipsylla tuta was 30.90 percent on Microtus fuscus plague. The infection rate of fleas and the flea index were the highest in October and the lowest in December and March. Species as Callopsylla sparsity, Amphipsylla tuta and Rhadinopsylla dahurica vicina could naturally infect the Yersinia pestis.

CONCLUSION

Microtus fuscus plague could become epidemic when animals and flea species were infected. We should emphasis on plague monitoring program so as to prevent the occurrence of the disease.

The vector of Hepatozoon sciuri

A description is given of the stages of sporogony of Hepatozoon sciuri, which have been found in three wild fleas (Orchopeas wickhami) out of a total of nearly sixty specimens collected from squirrels in England. Although an attempt to infect the fleas in the laboratory, by feeding them on infected squirrels, failed, the above findings indicate that these fleas may act as vectors of the squirrel parasite.

We wish to record our thanks to Professor P. C. C. Garnham for his kind interest and constructive suggestions regarding this work. We are specially indebted to Mrs M. Vizoso and to Dr J. F. D. Frazer for sending us fleas and squirrels from time to time. Our thanks are due to the authorities of the British Museum of Natural History for the identification of the flea.

Experiments on the olfactory responses and host-specificity of the Oriental rat flea (Xenopsylla cheopis), (Siphonaptera: Pulicidae)

Factors governing the response of the Oriental rat flea, X. cheopis, to the white rat and to three murids were studied in an olfactometer.

Starved females aged 5–10 days were attracted to white rats, whereas starved younger females were repelled or indifferent. Starved males, 1–10 days old, were either indifferent or were repelled.

No clear-cut attraction of 7- and 8-day-old starved females towards the murids Meriones tristrami, Acomys dimidiatus and Microtus guentheri was observed.

Starved females increased their weight during the first 8 days of life by 12·0%, while starved males lost 2·2%. Females kept in a vessel with a white rat showed a 115·2% weight gain, while males under the same conditions gained only 18·8% (Table 5).

The authors wish to thank Dr F. G. A. M. Smit, of the British Museum (Natural History), Tring, Hertfordshire (England), for his valuable help in the preparation of the manuscript for this paper.

A new schizogregarine, Mattesia orchopiae n.sp., in a flea of squirrels in England

A new schizogregarine Mattesia orchopiae, n.sp., parasitic in the flea Orchopeas wickhami, is described. The schizogony takes place in the fat-cells, while the gametogony and the sporogony occur in the Malpighian tubules. The micronuclear schizonts measured 13·7 × 11 μ. The trophozoites of the second schizogony measured 14·2 × 3·5 μ. The spores measured 10·5 × 7 μ.

After staining with toluidene blue metachromatic granules were found in the cytoplasm of the macronuclear schizonts and in the merozoites and the trophozoites resulting therefrom. Some of this metachromatic material could be removed by digestion with ribonuclease, while the rest of it persisted. Material stained with alcian blue was detected in the cytoplasm of the macronuclear schizonts.

I wish to thank Professor P. C. C. Garnham for encouragement and advice received during the conduct of this investigation, Mrs M. Vizoso and Miss K. Meedeniya for the supply of the fleas, the authorities of the British Museum for the identification of the fleas, and Sir W. P. MacArthur for his advice regarding the problem of nomenclature.

The bird fleas of Fair Isle

Approximately 5000 birds (78 species) were trapped on Fair Isle and examined for fleas. Six species of flea were recorded: D. g. gallinulae (430 records), C. gallinae (205 records), C. borealis (126 records), C. garei (4 records), C. fringillae and C. vagabundus (1 record each).

The infestation rate among spring-passage migrants was 52·2% and among autumn-passage migrants only 2·7%. Spring migrants released and retrapped after ‘de-fleaing’ in the Fair Isle apparatus showed a 55% re-infestation rate. On spring migrants D. g. gallinulae was the dominant flea, but on autumn migrants C. gallinae was dominant. The most heavily infested group of birds were the Turdidae (61% spring, 3% autumn infestation rate) and Sylviidae (53% spring, 1% autumn infestation rate).

A number of double and triple infestations with 2 or 3 species of flea is recorded. Double infestations involving D. g. gallinulae and C. borealis occur more frequently than would be expected for purely chance associations. More male birds (90) than female birds (70) were infested.

The sex ratio of the fleas (on the bodies of birds) was: D. g. gallinulae 294 males, 325 females; C. gallinae 115 males, 214 females; C. borealis 77 males, 77 females. On the spring migrants there was an excess of male D. g. gallinulae and on the autumn migrants an excess of females.

On the resident birds there was definite evidence of host preference. The starling was the chief host of C. gallinae, the pipits of D. g. gallinulae and the wheatear of C. borealis. The re-infestation rate of ‘de-fleaed’ retraps showed a higher rate than original trappings in all cases, but the lack of D. g. gallinulae on retrapped starlings suggested some host selection on the part of the flea.

The proportions of the three principal species of flea found in (i) the nest of the wheatear, and (ii) on the body of the bird were strikingly different.

Control of plague vectors on diurnal rodents in the Sierra Nevada of California by use of insecticide bait-boxes

Trials were conducted in the Sierra Nevada Mountains of California to test the effectiveness of 10% DDT dust in insecticide bait-box stations against the fleas of native diurnal rodents. The principle host species involved were the chipmunks Eutamias amoenus and E. speciosus, and the golden-mantled ground squirrel, Citellus lateralis. The important flea species were Monopsyllus eumolpi and M. ciliatus on chipmunks, and Diamanus montanus and Oropsylla idahoensis on ground squirrels. When baited daily for 12 days and furnished with 50 g. of 10% DDT dust, the bait-box stations reduced fleas strikingly within 24 hr., but very little residual control was obtained. A second application in which boxes were baited only twice weekly but for 28 days, also resulted in rapid knockdown and a residual control still effective 42 days after removal of the bait-boxes. The effect of the DDT was apparent at a distance of 400 ft. from the nearest bait-box due to the relatively extensive home ranges of the hosts. Although, in these trials, bait-box stations were spaced 100 ft. apart, 200 ft. spacing probably would be as effective with these hosts.

AN OUTBREAK OF MYXOMATOSIS CAUSED BY A MODERATELY ATTENUATED STRAIN OF MYXOMA VIRUS

Since the original epizootic of myxomatosis in this country (1953–55) carcasses of rabbits from outbreaks of the disease have been sent regularly to the Central Veterinary Laboratory, Weybridge, but no detailed investigations have been carried out on outbreaks of disease in natural populations in Great Britain since 1954 (Armour & Thompson, 1955). In July 1962 a rabbit was sent from the East Riding of Yorkshire and as a matter of routine this establishment was informed of the outbreak. The population of rabbits concerned was large and occupied an area of approximately 200 acres. The strain of virus causing the outbreak was attenuated and when this was discovered efforts were made to secure samples for as long as the outbreak lasted.

ELIMINATION OF EPERYTHROZOON COCCOIDES INFECTION FROM MOUSE COLONIES

1. Long-established infection of a mouse colony with Eperthyrozoon coccoides was eliminated by regular insecticidal treatments designed to reduce infestation with lice and fleas.

2. Undesirable consequences of E. coccoides infection upon mice used as experimental animals are noted and an easy routine for exclusion of this parasite from mouse colonies is suggested.