Medical and Veterinary Entomology
© Royal Entomological Society
Edited By: M. Cameron, D. Otranto
Impact Factor: 2.242
ISI Journal Citation Reports © Ranking: 2015: 10/138 (Veterinary Sciences); 14/94 (Entomology)
Online ISSN: 1365-2915
Volume 30, Issue 3
The impact of insecticide-treated cloth targets on the survival of Stegomyia polynesiensis (= Aedes polynesiensis) under laboratory and semi-field conditions in French Polynesia
E. W. Chambers, H. C. Bossin, S. A. Ritchie, R. C. Russell, S. L. Dobson
The impact of deltamethrin-impregnated cloth targets on Stegomyia polynesiensis (= Aedes polynesiensis) (Marks) (Diptera: Culicidae) was assessed under laboratory and semi-field settings in French Polynesia. Stegomyia polynesiensis females were released into small laboratory cages and large field cages containing either a deltamethrin-treated or an untreated navy blue cloth, and mosquito knock-down and mortality were assessed. The 24-h mortality rate in mosquitoes exposed to the insecticide-treated target in small cages was 98.0%. Read more here.
Volume 30, Issue 2
Comparison of novel and conventional methods of trapping ixodid ticks in the southeastern U.S.A.
S. E. Mays, A. E. Houston and R. T. Trout Fryxell
Tick-borne disease surveillance and research rely on resource-effective methods for tick collection. This study compared the respective performances of several trapping methods in a mixed grassland–forest habitat in western Tennessee. Read more here.
Volume 30, Issue 1
The impacts of larval density and protease inhibition on feeding in medicinal larvae of the greenbottle fly Lucilia sericata
M. R. Wilson, Y. Nigam, W. Jung, J. Knight and D. I Pritchard
Larval therapy, the therapeutic use of blowfly larvae to treat chronic wounds, is primarily used in debridement. There are, however, gaps in current knowledge of the optimal clinical application of the therapy and mechanisms of action in the debridement process. Using an artificial assay, two studies were undertaken to investigate these aspects of larval debridement by Lucilia sericata Meigen (Diptera: Calliphoridae); the first studied the effects of the density of larvae on tissue digestion and larval mass, and the second considered the effects on the same parameters of incorporating protease inhibitors into the feeding substrate. Read more here.
Volume 29, Issue 4
Rotation of male genitalia in various species of phlebotomine sandfly
J. Votýpka, M. Pavlasova, V. Volfova and P. Volf
Phlebotomine sandflies, vectors of Leishmania (Kinetoplastida: Trypanosomatidae) parasites that affect millions of people worldwide, breed in terrestrial biotopes. As immature stages are rarely accessible, the detection of their natural breeding sites is primarily based on findings of juvenile males with unrotated external genitalia. Read more here.
Rhipicephalus rossicus, a neglected tick at the margin of Europe: a review of its distribution, ecology and medical importance
A. D. Mihalca, Z. Kalmar and M. O. DumitRache
Rhipicephalus rossicus (Ixodida: Ixodidae) is a three-host tick with a broad host spectrum that includes wild animals, pets, livestock and humans. Despite its local abundance in certain areas, most of the available information on R. rossicus was published decades ago, mainly by former soviet authors. Its distribution largely overlaps the Eurasian steppe. Read more here.
Observations on changes in abundance of questing Ixodes ricinus, castor bean tick, over a 35-year period in the eastern part of its range (Russia, Tula region)
Yu. Korotkov, T. Kozlova And L. Kozlovskaya
Ixodes ricinus (Acari: Ixodidae) L. transmit a wide variety of pathogens to vertebrates including viruses, bacteria and protozoa. Understanding of the epidemiology of tick-borne infections requires basic knowledge of the regional and local factors influencing tick population dynamics. The present study describes the results of monitoring of a questing I. ricinus population, conducted over 35 years (1977–2011) in the eastern, poorly studied part of its range (Russia, Tula region). Read more here.
Temporospatial fate of bacteria and immune effector expression in house flies fed GFP-Escherichia coli O157:H7
A. Fleming, H. V. Kumar, C. Joyner, A. Reynolds, and D. Nayduch
Fleming et al. demonstrated the fate of E. coli O157:H7 in house flies by feeding individual droplets of GFP-expressing bacteria (center) and tracking bacteria over time by microscopy of the fly gut and culture enumeration (top). Concurrent qRTPCR analysis of antimicrobial effector gene expression (bottom) revealed that flies primarily mount local responses against ingested bacteria. The ephemeral association between E. coli O157:H7 and house flies may be hastened by fly defenses. Read more here.
The use of essential oils in veterinary ectoparasite control: a review
L. Ellse, R. Wall
There is a growing body of evidence indicating the potential value of essential oils as control agents against a range of arthropod ectoparasites, particularly lice, mites and ticks. Toxicity has been demonstrated following immersion and physical contact with treated surfaces, as well as after exposure to the vapour of these oils; the last of these factors implies that there is a neurotoxic, rather than simply a mechanical, pathway in their mode of action. However, the volatile nature of essential oils suggests that their residual activity is likely to be short-lived. A possible advantage of essential oils over conventional ectoparasite treatments may refer to their reported ovicidal efficacy, although it is unclear whether this results from neurotoxicity or mechanical suffocation... Read more here.
The Mondrian matrix: Culicoides biting midge abundance and seasonal incidence during the 2006–2008 epidemic of bluetongue in the Netherlands
R. Meiswinkel, F. Scolamacchia, M. Dik, J. Mudde, E. Dijkstra, I. J. K. Van Der Ven and A. R. W. Elbers
During the northern Europe epidemic of bluetongue (BT), Onderstepoort-type blacklight traps were used to capture Culicoides Latreille (Diptera: Ceratopogonidae) biting midges weekly between November 2006 and December 2008 on 21 livestock farms in the Netherlands... Read more here.
Image: Mondrian Matrix of the weekly Culicoides abundances (colour-coded) in the Netherlands for 2007 and 2008
Effect of oral infection of La Crosse virus on survival and fecundity of native Ochlerotatus triseriatus and invasive Stegomyia albopicta
K. S. Costanzo, E. J. Muturi, A. V. Montgomery, B. W. Alto
Arboviruses can have benign, deleterious, or beneficial effects on the vector. We tested the hypothesis that oral infection with La Crosse virus (LACV) will have little to no effect on mosquito longevity and fecundity, a prediction of low virulence selected in a system with frequent vertical transmission. We tested the effects of infection in native Ochlerotatus triseriatus Say and invasive Stegomyia albopicta Skuse (Diptera: Culicidae). We artificially fed adult female mosquitoes of each species with either LACV-infected or uninfected bovine blood and determined adult longevity and fecundity. For females fed LACV-infected blood, bodies and legs, respectively, were separately homogenized and assayed by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) to determine the LACV infection and dissemination rates. Ochlerotatus triseriatus had a higher infection and dissemination rate than St. albopicta. For both species, female size had no effect on infection status. Infection status also had no effect on longevity or fecundity for both species. We suggest that the high frequency of vertical transmission may have selected for strains of the virus with low virulence in two vectors, in spite of their different evolutionary histories with the virus.
Image: The eastern treehole mosquito (Aedes triseriatus) Say, a primary vector of La Crosse virus (Bunyaviridae). Image taken by James Newman, Florida Medical Entomology Laboratory.
Assortative mating in mixed swarms of the mosquito Anopheles gambiae s.s. M and S molecular forms, in Burkina Faso, West Africa
K. R. Dabire, S. Sawadodgo, A. Diabate, K. H. Toe, P. Kengne, A. Ouari, C. Costantini, C. Gouagna, F. Simard, T. Baldet, T. Lehmann, G. Gibson
The molecular form composition of Anopheles gambiae Giles s.s. (Diptera: Culicidae) mating swarms and the associated mating pairs (copulae) were investigated during two rainy seasons (July to October, 2005 and July to November, 2006) in the villages of Soumousso and Vallée du Kou (VK7). Although the habitats of these villages differ markedly, sympatric populations of M and S molecular forms of An. gambiae s.s. occur in both places periodically. The main aim was to assess the degree to which these molecular forms mate assortatively. In Soumousso, a wooded savannah habitat, the majority of swarm samples consisted of only S-form males (21/28), although a few M-form males were found in mixed M- and S-form swarms. In VK7, a rice growing area, the majority of swarm samples consisted of only M-form males (38/62), until October and November 2006, when there were nearly as many mixed-form as single-form swarms. Overall, ∼60% of M- and S-form swarms were temporally or spatially segregated; the two forms were effectively prevented from encountering each other. Of the remaining 40% of swarms, however, only about half were single-form and the rest were mixed-form. Of the 33 copulae collected from mixed-form swarms, only four were mixed-form pairs, significantly fewer than expected by random pairing between forms (χ2 = 10.34, d.f. = 2, P < 0.01). Finally, all specimens of inseminated females were of the same form as the sperm contained within their spermatheca (n = 91), even for the four mixed-form copulae. These findings indicate that assortative mating occurs within mixed-form swarms, mediated most probably by close-range mate recognition cues.
Image: Swarm of An. gambiae s.s. in Vallée du Kou (VK7)
Phlebotomine sandflies and the spreading of leishmaniases and other diseases of public health concern
M. Maroli, M. D. Feliciangeli, L. Bichaud, R. N. Charrel, L. Gradoni
Phlebotomine sandflies transmit pathogens that affect humans and animals worldwide. We review the roles of phlebotomines in the spreading of leishmaniases, sandfly fever, summer meningitis, vesicular stomatitis, Chandipura virus encephalitis and Carrión's disease. Among over 800 species of sandfly recorded, 98 are proven or suspected vectors of human leishmaniases; these include 42 Phlebotomus species in the Old World and 56 Lutzomyia species in the New World (all: Diptera: Psychodidae). Based on incrimination criteria, we provide an updated list of proven or suspected vector species by endemic country where data are available. Increases in sandfly diffusion and density resulting from increases in breeding sites and blood sources, and the interruption of vector control activities contribute to the spreading of leishmaniasis in the settings of human migration, deforestation, urbanization and conflict. In addition, climatic changes can be expected to affect the density and dispersion of sandflies. Phlebovirus infections and diseases are present in large areas of the Old World, especially in the Mediterranean subregion, in which virus diversity has proven to be higher than initially suspected. Vesiculovirus diseases are important to livestock and humans in the southeastern U.S.A. and Latin America, and represent emerging human threats in parts of India. Carrión's disease, formerly restricted to regions of elevated altitude in Peru, Ecuador and Colombia, has shown recent expansion to non-endemic areas of the Amazon basin.
Image: Phlebotomus perniciosus mating before a blood meal taken by the female in laboratory.
Previous reports of Cephenemyia jellisoni Townsend (Diptera: Oestridae) larvipositing onto the lips/lower muzzle of deer, with larvae invading via the mouth, are shown to be erroneous. Additional studies with deer models baited with CO2, 1-octen-3-ol and Deer Trail Scent, and muzzle and nostrils treated with insect adhesive, revealed that only C. apicata Bennett & Sabrosky larviposited onto the lips/lower muzzle; C. jellisoni, by contrast, larviposited into the nostrils. Larval depositions were associated with females of both species observed attacking models. Females of both species also were found stuck on adhesive-treated, baited models not attended by observers. During several seasons of exposure, such models received 89 C. jellisoni larvipositions into the nostrils and 87 C. apicata larvipositions onto the lips/lower muzzle. In laboratory experiments nearly all larvae of both species remained stuck in adhesive within 1 mm or less of where they were deposited.
Image: Group of C. apicata larvae encased in globule of uterine fluid that did not dissolve in insect adhesive (×10).
Detection of Rickettsia spp. and host and habitat associations of fleas (Siphonaptera) in eastern Taiwan
C. C. KUO, J. L. HUANG, T. E. LIN, H. C. WANG
Rickettsia typhi and Rickettsia felis (Rickettsiales: Rickettsiaceae) are two rickettsiae principally transmitted by fleas, but the detection of either pathogen has rarely been attempted in Taiwan. Of 2048 small mammals trapped in eastern Taiwan, Apodemus agrarius Pallas (24.5%) and Mus caroli Bonhote (24.4%) (both: Rodentia: Muridae) were the most abundant, and M. caroli hosted the highest proportion of fleas (63.9% of 330 fleas). Two flea species were identified: Stivalius aporus Jordan and Rothschild (Siphonaptera: Stivaliidae), and Acropsylla episema Rothschild (Siphonaptera: Leptopsyllidae). Nested polymerase chain reaction targeting parts of the ompB and gltA genes showed six fleas to be positive for Rickettsia spp. (3.8% of 160 samples), which showed the greatest similarity to R. felis, Rickettsia japonica, Rickettsia conorii or Rickettsia sp. TwKM01. Rickettsia typhi was not detected in the fleas and Rickettsia co-infection did not occur. Both flea species were more abundant during months with lower temperatures and less rainfall, and flea abundance on M. caroli was not related to soil hardness, vegetative height, ground cover by litter or by understory layer, or the abundance of M. caroli. Our study reveals the potential circulation of R. felis and other rickettsiae in eastern Taiwan, necessitating further surveillance of rickettsial diseases in this region. This is especially important because many novel rickettsioses are emerging worldwide.
Image: Acropsylla episema - female
Responses of Amblyomma americanum and Dermacentor variabilis to odorants that attract haematophagous insects
A. L. Carr, R. M. Roe, C. Arellano, D. E. Sonenshine, C. Schal, C. S. Apperson
Carbon dioxide (CO2), 1-octen-3-ol, acetone, ammonium hydroxide, L-lactic-acid, dimethyl trisulphide and isobutyric acid were tested as attractants for two tick species, Amblyomma americanum and Dermacentor variabilis (Acari: Ixodidae), in dose–response bioassays using Y-tube olfactometers. Only CO2, acetone, 1-octen-3-ol and ammonium hydroxide elicited significant preferences from adult A. americanum, and only CO2 was attractive to adult D. variabilis. Acetone, 1-octen-3-ol and ammonium hydroxide were separately evaluated at three doses against CO2 (from dry ice) at a field site supporting a natural population of A. americanum nymphs and adults. Carbon dioxide consistently attracted the highest number of host-seeking ticks. However, for the first time, acetone, 1-octen-3-ol and ammonium hydroxide were shown to attract high numbers of A. americanum. Further research is needed to determine the utility of these semiochemicals as attractants in tick surveillance and area-wide management programmes.
Image: Amblyomma americanum - female
The effects of host-related, parasite-related and environmental factors on the diversity and abundance of two ectoparasite taxa, fleas (Insecta: Siphonaptera) and mites (Acari: Mesostigmata), parasitic on small mammals (rodents and marsupials), were studied in different localities across Brazil. A stronger effect of host-related factors on flea than on mite assemblages, and a stronger effect of environmental factors on mite than on flea assemblages were predicted. In addition, the effects of parasite-related factors on flea and mite diversity and abundance were predicted to manifest mainly at the scale of infracommunities, whereas the effects of host-related and environmental factors were predicted to manifest mainly at the scale of component and compound communities.
Image: Polygenis (Polygenis) bohlsi jordani (Siphonaptera: Rhopalopsyllidae) - male
Insect repellents and associated personal protection for a reduction in human disease
M. Debboun And D. Strickman
Personal protection measures against biting arthropods include topical insect repellents, area repellents, insecticide-treated bednets and treated clothing. The literature on the effectiveness of personal protection products against arthropods is mainly limited to studies of prevention of bites, rather than prevention of disease. Tungiasis was successfully controlled by application of topical repellents and scrub typhus was reduced through the use of treated clothing.
Image: Partially engorged adult bed bug (Cimex lectularius) blood feeding on a human.
Responses of tsetse flies, Glossina morsitans morsitans and Glossina pallidipes, to baits of various size
S. J. Torr, A. Chamis, G. A. Vale, M. J. Lehane, J. M. Lindh
Recent studies of Palpalis group tsetse [Glossina fuscipes fuscipes (Diptera: Glossinidae) in Kenya] suggest that small insecticide-treated targets will be more cost-effective than the larger designs currently used to control tsetse. Studies were undertaken in Zimbabwe to assess whether small targets are also more cost-effective for the Morsitans group tsetse, Glossina morsitans morsitans and Glossina pallidipes.
Images – Left: Example of a Tsetse target; Right: A female tsetse fly giving birth.
Hen dustbathing in sand plus very fine, inert dust materials (diatomaceous earth, kaolin clay, or sulfur) suppresses northern fowl mite or body louse numbers. For the diatomaceous earth or kaolin (a widespread natural substrate), only hens that actually used the boxes reduced ectoparasite numbers, while even non-user hens benefitted from presence of sulfur dust in the houses. Dustbathing in coarser, natural debris in the hen houses, or in residual sand itself (once substantial amounts of the finer dusts were dispersed), did not control ectoparasites. This provides experimental evidence that providing dustboxes can aid in controlling ectoparasites, and suggests that the behavior may be adaptive (in addition to the documented feather maintenance function). A key remaining practical and fundamental question is why certain hens use the resource, while others do not.