Coccidiosis in European rabbit (Oryctolagus cuniculus algirus) populations in the Iberian Peninsula

The European rabbit Oryctolagus cuniculus is a keystone species from the Iberian Peninsula where viral diseases have played a prominent role in regulating their populations. Coccidiosis, a parasitic disease caused primarily by Eimeria spp., is also thought to have important negative effects. However, few studies have investigated the impact of coccidia on wild European rabbit populations on the Iberian Peninsula. Here we estimate coccidian prevalence in rabbit faecal samples collected along transects established in two ecological regions. Six Eimeria species, with different pathogenicity, were identified (E. coecicola, E. perforans, E media, E. magna, E. irresidua and E. flavescens). Species diversity varied significantly between regions although mean oocyst excretion levels were generally low in both areas (57.61 s.d.±78.07 and 17.03 s.d.±27.72, oocyst per gram of rabbit faeces). This study is the first to describe the composition of the Eimeria spp. assemblage for wild rabbit populations on the Iberian Peninsula and provides fundamental information for future studies on the potential interaction of viral and parasitic diseases.

Control of Tick Infestations in Oryctolagus cuniculus (Lagomorpha: Leporidae) With Spinosad Under Laboratory and Field Conditions

Because of great economic loss in the world's livestock industry, and the serious risks to human health, the control of ticks and tick-borne diseases is one of the most important health management issues today. Current methodology involves integrated tick control for preventing the development of resistance. Rabbits are hosts for immature stages of the three-host tick Hyalomma lusitanicum Koch; so, we focus on this host as a strategy to interrupt the tick life cycle. Spinosad is an insecticide-acaricide, produced by the fermentation of metabolites of the actinomycete bacterium Saccharopolyspora spinosa. We administered spinosad orally by force-feeding naturally and artificially infested rabbits, and under field conditions by administering treated food via a hopper during the period of peak infestation and reinfestation risk for rabbits. No living larvae were recovered from treated laboratory rabbits. In naturally infested rabbits, the number of live ticks collected from treated rabbits (mean = 0.62 ticks per ear) was significantly lower than those recovered from untreated rabbits (mean = 7.27; P < 0.001), whereas the number of dead ticks collected from untreated rabbits (mean = 6.53) was significantly lower than those recovered from treated rabbits (mean = 18.62; P < 0.001). In addition, free and continually reinfested rabbits freely ingested low doses of spinosad, reducing the tick burden from 48.00 (Day 0) to 26.09 ticks per ear in treated rabbits (Day 16), whereas controls maintained the infection (46.64). This strategy could be useful as an alternative or supplement to traditional acaricides in tick control programs.

Insect Colonization and Succession on Rabbit Carcasses in Southwestern Mountains of the Kingdom of Saudi Arabia

This study describes for the first time the necrophagous insects attracted to carcasses of the European rabbit in the mountains of Al-Baha Province of southwestern Kingdom of Saudi Arabia (KSA). Twenty-four rabbit carcasses were exposed in 2010 during spring (March, April, and May), summer (June, July, and August), and autumn (September, October, and November). The calliphorid fly species, Calliphora vicina Robineau-Desvoidy, Chrysomya marginalis (Wiedemann), Chrysomya chloropyga (Wiedemann), Chrysomya albiceps (Wiedemann), and Lucilia cuprina (Wiedemann), the sarcophagid Liosarcophaga babiyari (Lehrer), and muscoid flies Musca domestica (L.) and Musca stabulans Fallén were attracted to the carcasses. Seven species of Coleoptera, the dermestid Dermestes maculatus (De Geer), three species of hister beetles, Saprinus moyses Marseul, Saprinus ruber gemminigeri, and Saprinus chalcites (Illiger), the tenebrionid Himatismus sp., the clerid species, Necrobia ruficollis (F.), and the staphylinid beetle Creophilous maxillosus (L.) were also attracted to the rabbit carcasses. One species of adult pteromalid fly pupal parasitoid Nasonia sp. was also collected. The dominant larvae on all the rabbit carcasses were Ch. albiceps, L. cuprina, and Li. babiyari. Insect activity caused rabbit carcasses to decompose faster during summer (21.38 ± 0.49 d) compared with spring (27.5 ± 0.73 d) and autumn (30.38 ± 0.50 d). This study indicates that in this region of KSA, Ch. albiceps, L. cuprina, and Li. babiyari are species useful for estimating minimal postmortem intervals.

Infections do not predict shedding in co-infections with two helminths from a natural system

Given the health and economic burden associated with the widespread occurrence of co-infections in humans and agricultural animals, understanding how coinfections contribute to host heterogeneity to infection and transmission is critical if we are to assess risk of infection based on host characteristics. Here, we examine whether host heterogeneity to infection leads to similar heterogeneity in transmission in a population of rabbits single and co-infected with two helminths and monitored monthly for eight years. Compared to single infections, co-infected rabbits carried higher Trichostrongylus retortaeformis intensities, shorter worms with fewer eggs in utero, and shed similar numbers of parasite eggs. In contrast, the same co-infected rabbits harbored fewer Graphidium strigosum with longer bodies and more eggs in utero, and shed more eggs of this helminth. A positive density-dependent relationship between fecundity and intensity was found for T. retortaeformis but not G. strigosum in co-infected rabbits. Juvenile rabbits contributed to most of the infection and shedding of T. retortaeformis, while adult hosts were more important for G. strigosum dynamics of infection and transmission, and this pattern was consistent in single and co-infected individuals. This host-parasite system suggests that we cannot predict the pattern of parasite shedding during co-infections based on intensity of infection alone. We suggest that a mismatching between susceptibility and infectiousness should be expected in helminth coinfections and should not be overlooked.

Morphological characteristics and developmental changes of the ovary in the tick Haemaphysalis longicornis Neumann

Haemaphysalis longicornis (Ixodida: Ixodidae) is an important vector of transovarially transmitted parasites of the genus Babesia (Piroplasmida: Babesiidae). In the present study, we investigated the morphological characteristics and developmental changes of the ovary of H. longicornis. We show that the ovary of H. longicornis has a single tubular structure and is surrounded by a tunica propria. There is a longitudinal groove along one side of the ovary. During feeding and after engorgement, great changes can be observed in the ovary of H. longicornis and two rapid growth phases can be detected. The number of major protein bands of the ovary is significantly increased from day 3 of feeding and reaches a maximum on the day of engorgement. Therefore, the great diversity of proteins in the ovaries of H. longicornis can facilitate the identification of new targets for vaccine development.

The first recorded outbreak of cryptosporidiosis due to Cryptosporidium cuniculus (formerly rabbit genotype), following a water quality incident

We report the first identified outbreak of cryptosporidiosis with Cryptosporidium cuniculus following a water quality incident in Northamptonshire, UK. A standardised, enhanced Cryptosporidium exposure questionnaire was administered to all cases of cryptosporidiosis after the incident. Stool samples, water testing, microscopy slides and rabbit gut contents positive for Cryptosporidium were typed at the Cryptosporidium Reference Unit, Singleton Hospital, Swansea. Twenty-three people were microbiologically linked to the incident although other evidence suggests an excess of 422 cases of cryptosporidiosis above baseline. Most were adult females; unusually for cryptosporidiosis there were no affected children identified under the age of 5 years. Water consumption was possibly higher than in national drinking water consumption patterns. Diarrhoea duration was negatively correlated to distance from the water treatment works where the contamination occurred. Oocyst counts were highest in water storage facilities. This outbreak is the first caused by C. cuniculus infection to have been noted and it has conclusively demonstrated that this species can be a human pathogen. Although symptomatically similar to cryptosporidiosis from C. parvum or C. hominis, this outbreak has revealed some differences, in particular no children under 5 were identified and females were over-represented. These dissimilarities are unexplained although we postulate possible explanations.

Characterisation and analysis of thioredoxin peroxidase as a potential antigen for the serodiagnosis of sarcoptic mange in rabbits by dot-ELISA

BACKGROUND

Scabies caused by Sarcoptes scabiei is a widespread but a neglected tropical zoonosis. In this study, we characterised a S. scabiei thioredoxin peroxidase (SsTPx) and evaluated a recombinant SsTPx as a diagnostic antigen in rabbits.

METHODS

The open reading frame of the gene encoding SsTPx-2 was amplified and the recombinant protein was expressed in Escherichia coli cells and purified. SsTPx was localized in mite tissue by immunolocalisation using the purified recombinant protein. Serodiagnosis assays were carried out in 203 New Zealand White rabbit serum samples by dot-ELISA.

RESULT

The open reading frame (489 bp) of the gene encodes an 18.11 kDa protein, which showed highly homology to that of Psoroptes cuniculi (98.77% identity) and belongs to the 2-Cys family of peroxiredoxins. SsTPx was mainly distributed in muscle tissues of mites, integument of the epidermis and the anterior end of S. scabiei. Although SsTPx cross-reactivity with psoroptic mites was observed, the SsTPx dot-ELISA showed excellent diagnostic ability, with 95.3% sensitivity and 93.8% specificity in mange-infected and uninfected groups.

CONCLUSIONS

This study showed that the purified SsTPx is a highly sensitive antigen for the diagnosis of mange infection by dot-ELISA. This technique is a rapid and convenient method that can be used worldwide for the clinical diagnosis of sarcoptic mange in rabbits, and is especially useful in developing regions.

Climate changes influence free-living stages of soil-transmitted parasites of European rabbits

Climate warming has been suggested to augment the risk of infectious disease outbreaks by extending the seasonal window for parasite growth and by increasing the rate of transmission. Understanding how this occurs in parasite-host systems is important for appreciating long-term and seasonal changes in host exposure to infection and to reduce species extinction caused by diseases. We investigated how free-living stages of two soil-transmitted helminths of the European rabbit (Oryctolagus cuniculus) responded to experimental changes in temperature by performing laboratory experiments with environmental chambers and field manipulations using open-top-chambers. This study was motivated by our previous observations that air temperature has increased over the last 30 years in our field site and that during this period intensity of infection of Graphidium strigosum but not Trichostrongylus retortaeformis was positively associated with this temperature increase. Laboratory and field experiments showed that both parasites accelerated egg development and increased hatching rate and larval survival in response to accumulating thermal energy. Both parasites behaved similarly when exposed to diverse temperature regimes, decadal trends, and monthly fluctuations, however, T. retortaeformis was more successful than G. strigosum by showing higher rates of egg hatching and larval survival. Across the months, the first day of hatching occurred earlier in warmer conditions suggesting that climate warming can lengthen the period of parasite growth and host exposure to infective stages. Also, T. retortaeformis hatched earlier than G. strigosum. These findings showed that seasonal changes in intensity, frequency, and duration of daily temperature are important causes of variability in egg hatching and larva survival. Overall, this study emphasizes the important role of climate warming and seasonality on the dynamics of free-living stages in soil-transmitted helminths and their contribution to enhance host exposure to parasitic infections. Yet, the ability to infect might ultimately depend on how hosts interact with parasites.

Evaluation of the effect of various concentrations of selected pyrethroids on the development of Dermacentor reticulatus eggs and larvae

The Palearctic three-host species Dermacentor reticulatus contributes to the circulation of numerous pathogens in the environment. Reduction of its abundance may therefore decrease the risk of tick-borne diseases in a given area. The aim of the study is to determine the effect of various concentrations of three pyrethroids--(D), cypermethrin (C), and alpha-cypermethrin (AC) on the development of D. reticulatus eggs and larvae. 217 engorged D. reticulatus females were examined in the investigations. After the feeding period, they were sprayed with 0.015625%, 0.03125%, 0.0625%, and 0.125% solutions of D, C, and AC, and kept at a temperature of 25 o C and 90% relative humidity throughout the preoviposition and oviposition periods. Eggs laid by females were kept in the same conditions until larval hatch. Based on the results obtained, parameters of the course of maturation and oviposition, as well as parameters of embryonic development, were determined. The investigations showed that the pyrethroids tested prolonged the egg maturation period, reduced the number and weight of eggs, and caused disturbances in embryogenesis in D. reticulatus. Upon treatment with as little as 0.015625% AC, larvae did not develop and all eggs died 1-2 days after oviposition. C led to a decreased percentage of normal larval hatch--31.96%, 15.51% and 12.5%, respectively, after using three increasing concentrations (control 98.15%), and a high rate of egg and embryo mortality. The least detrimental effect on the D. reticulatus maturation and embryonic periods was exerted by deltamethrin (82.74%, 84.37% and 16.80% of normal larvae in treatment with the three concentrations). Morphological anomalies were observed in larvae during the experimental period. AC appeared to have the most toxic effect during the maturity and egg development periods, while C exhibited lower toxicity. Application of these pyrethroids in engorged D. reticulatus females exerts distant effects that lead to substantial reduction of tick offspring abundance.

Organic parasite control for poultry and rabbits in British Columbia, Canada

Plants used for treating endo- and ectoparasites of rabbits and poultry in British Columbia included Arctium lappa (burdock), Artemisia sp. (wormwood), Chenopodium album (lambsquarters) and C. ambrosioides (epazote), Cirsium arvense (Canada thistle), Juniperus spp. (juniper), Mentha piperita (peppermint), Nicotiana sp. (tobacco), Papaver somniferum (opium poppy), Rubus spp. (blackberry and raspberry relatives), Symphytum officinale (comfrey), Taraxacum officinale (common dandelion), Thuja plicata (western redcedar) and Urtica dioica (stinging nettle).

Secretory process of salivary glands of female Amblyomma cajennense (Acari: Ixodidae) ticks fed on resistant rabbits

Ticks have great economic and health importance since infested animals have reduced milk and meat production, and, besides that, they are expensive ectoparasites to control. While feeding, ticks can transmit to their hosts a large amount of pathogens, including Rickettsia rickettsii responsible for the "spotted fever" or "fever of the mountains." It is known that animals infested with ticks or artificially immunized with their salivary gland extracts develop resistance, which is related to a decrease in engorged female weight, in egg-laying by adults, in egg viability and, in some cases, in the capacity of pathogens transmission. The present study aimed to examine morpho-histochemically the female salivary glands of semi and engorged Amblyomma cajennense fed on resistant rabbits. The results revealed that acinus I had no changes when compared to that of females fed on naive rabbits. The c cells of acinus II showed signs of early degeneration, which may result in feeding efficiency decrease. In acinus III d cells, activity time was longer. Such occurrence was associated with the time of female fixation, which increased in females fed on resistant hosts.

Eimeria species in wild rabbits (Oryctolagus cuniculus) in Fars province, Iran

This investigation was accomplished during February to November 2008. A total of 71 wild rabbits (Oryctolagus cuniculus) of about 5 to 12 months age were collected alive from different parts of Fars province, south of Iran. Faecal sampling was carried out directly from recti and the oocysts were isolated using sedimentation and floatation techniques and the sporulated oocyst were identified based on morphological and biological characteristics. All the rabbits were apparently healthy and showed no clinical symptoms. Twenty two rabbits (31.0%) were positive for infection with Eimeria and six species including Eimeria perforans (18.3%), Eimeria magna (16.9%), Eimeria media (14.1), Eimeria irresidua (11.2%), Eimeria flavescens (4.2%), and Eimeria coecicola (2.8%) were identified. Eighty six percent of the infected rabbits showed mixed infections with two or three Eimeria species. Lack of clinical signs could be due to the agro ecological and environmental conditions of rabbit habitats specifically dry and hot climatic features in recent years. In addition, immunity induced by long term exposure to low doses of oocysts shedded by the carrier animals probably have pivotal role in impairing parasitic developmental cycles and preventing acute coccidiosis.

Prevalence, infectivity and oocyst sporulation time of rabbit-coccidia in Taiwan

Prevalence of Eimeria species parasitizing rabbits (Oryctolagus cuniculus) in Taiwan were investigated. Six Eimeria species, namely: Eimeria media (prevalence, 158/642; 24.6%), Eimeria magna (101/642; 15.7%), Eimeria perforans (58/642; 9.0%), Eimeria coecicola (46/642; 7.2%), Eimeria piriformis (16/642; 2.5%), and Eimeria exigua (9/642; 1.4%) were observed. The overall prevalence of these coccidial infections in rabbits from pet shops and farms was 46.2% and 41.7%, respectively. Concurrent infections involving 2 or 3 species were often observed, while quadruple-infection was rare. Significant differences (p < 0.005) in prevalence were observed between the adult and juvenile rabbits. The minimum time required for oocyst sporulation of E. media, E. piriformis, E. magna, E. perforans, E. exigua, E. coecicola were 10, 20, 32, 12, 16, and 36 hr, respectively. This is the first report on the prevalence of Eimeria intestinal infection in commercial domestic rabbits in Taiwan. We demonstrated that these rabbit-infecting Eimeria species have high biopotential in that the ingestion of a single sporulated oocyst could successfully produce patent infection in a rabbit. In addition, they also possess high host specificity in that they could not infect mice, golden hamsters, Mongolian gerbils, rats, and guinea pigs.

Beyond splitting hares and rabbiting on about major histocompatibility complex complexity

The genes of the major histocompatibility complex (MHC) have become the target of choice for studies wishing to examine adaptively important genetic diversity in natural populations. Within Molecular Ecology alone, there have been 71 papers on aspects of MHC evolution over the past few years, with an increasing year on year trend. This focus on the MHC is partly driven by the hypothesized links between MHC gene dynamics and ecologically interesting and relevant traits, such as mate choice and host–parasite interactions. However, an ability to pin down the evolutionary causes and ecological consequences of MHC variation in natural populations has proven challenging and has been hampered by the very issue that is attractive about MHC genes – their high levels of diversity. Linking high levels of MHC diversity to ecological factors in inherently complex natural populations requires a level of experimental design and analytical rigour that is extremely difficult to achieve owing to a plethora of potentially confounding and interacting variables. In this issue of Molecular Ecology, Smith et al. (2010) elegantly overcome the challenge of detecting complex interactions in complex systems by using an intricate analytical approach to demonstrate a role for MHC in the reproductive ability of a natural population of the European hare Lepus europaeus (Fig. 1). Also in this issue, Oppelt et al. (2010) demonstrate a role for MHC variation in determining levels of hepatic coccidian infection in the European rabbit Oryctolagus cuniculus (Fig. 2).

An accidental but safe and effective use of Lucilia cuprina (Diptera: Calliphoridae) in maggot debridement therapy in Alexandria, Egypt

The calliphorid fly, Lucilia cuprina (Wiedemann), is known to cause serious malign myiasis in animals, whereas its sibling species Lucilia sericata (Meigen) is commonly a carrion breeder and is used in maggot debridement therapy (MDT). The current study reports an accidental involvement of L. cuprina in MDT in Alexandria, Egypt, that has proved to be safe and effective. In November 2008, the laboratory colonies of L. sericata (the species regularly used in MDT) at the Faculty of Science, Alexandria University were renewed by Lucilia flies collected as third instar larvae on exposed rabbit carcasses. Flies from the new colonies were successfully used to heal the diabetic foot wounds of two patients at Alexandria Main University Hospital. Analysis of DNA sequences and adult and larval morphology then revealed that these flies were and still are L. cuprina. Breeding of this species in carrion in Alexandria is a new record. Despite the safety of this strain of L. cuprina in MDT, entomologists rearing blow flies for the purpose of wound debridement should regularly maintain high quality assurance of their species' identity to avoid possible clinical complications that may result from the introduction of an unexpected and invasive species to their laboratory colonies.

[Helminths of some laboratory animals detected by necropsy and fecal examination]

A study was performed in order to determine helminths of laboratory animals. Fecal specimens obtained from 110 mice, 263 rats and 65 rabbits were investigated and 37 rats and 7 rabbits were necropsied. In general, 83.8% rats were found to be infected by necropsy, while 100% of mice,and 81.8% of rats were found to be infected with one or more helminths species by fecal examination. No rabbits were found to be infected by necropsy or fecal examination. In fecal examination of mice and rats, the prevalence of helminths was detected as follows: Syphacia muris, 100%; Aspicularis tetraptera, 53.6%; Syphacia obvelata, 46.4%; and Hymenolepis diminuta 17.9% in mice. The prevalence in rats was H. Diminuta, 62.5%; S. muris, 25%; Hymenolepis nana, 6.8%; and Trichosomoides crassicauda, 6.8%. In necropsy, S. muris was identified in all of infected rats, but only one was infected with A. tetraptera.

Comparison of efficacy of ivermectin and doramectin against mange mite (Sarcoptes scabiei) in naturally infested rabbits in Turkey

The authors used 14 New Zealand rabbits (5 naturally infested rabbits and 9 in-contact rabbits) for Sarcoptes scabiei treatment in this study. Signs, such as itchy ears, eyes, tail and abdominal skin, alopecia and pyoderma, were considered to be the cause of these disorders. Infested rabbits were grouped according to the intensity of S. scabiei infestation (low, medium and high). Each group was then divided into two subgroups; in one subgroup the rabbits received ivermectin (1%) and, in the other, doramectin (1%). All subgroups received a subcutaneous injection at a dosage of 400 microg/kg body weight every 80 h on three occasions. On day 28 after commencing the treatment, all the rabbits in the first two groups had recovered completely. Although both drugs were applied at the same time and at the same dose, the third group (high degree of infestation), revealed, both microscopically and macroscopically, that ivermectin has more rapid effect than doramectin. Treatment was effective in all groups.

On Dipetalonema manson-bahri n.sp., from the Spring-hare, Pedetes surdaster larvalis, with a Note on its Development in Fleas

1. The morphology of the adult worms and the microfilariae are described of a new species of filarial worm, Dipetalonema manson-bahri.

2. Dehpsylla crassipes Jordon, 192G, a flea specific to Pedetes surdasler, was found in nature to contain infective larvae which are believed to be those of D. manson-bahri.

3. In the laboratory full development of D. manson-bahri was observed in Ctenocephalides felis and Xenopsylla cheopis.

European rabbits (Oryctolagus cuniculus) are naturally infected with different Trypanosoma cruzi genotypes

Trypanosoma cruzi, the etiologic agent of Chagas disease, presents a complex life cycle, cycling between reduviid vectors and wild and domestic mammals. The European rabbit is an introduced species in America, but its role as reservoir in the wild transmission cycle of Chagas disease remains unknown. We used polymerase chain reaction, Southern blot, and hybridization tests to detect infection and characterize genotypes in rabbits from a hyperendemic area of Chagas disease in Chile. Results show 38% of infection with different genotypes. We provide evidence that rabbits are naturally infected with T. cruzi, which may have important epidemiologic consequences for the wild transmission cycle.

[Dynamics of endoparasite infections in rabbits at different rearing regimes]

This study was intended to evaluate the occurrence and seasonality of infection of coccidian and helminth parasites, in three rabbit warrens differently managed. Mothers stayed with their offspring on deep litter (farm A, 90 dams), in boxes cleaned weekly (farm B, 30 dams) or on slatted floor (farm C, 10 females), whereas all the young after weaning (1 to 5 months of age) were kept in cages with slatted floor. Animals were fed a complete balanced pelleted feed (warrens A and B) or traditional forage (herd C). Antiparasitic treatment involved coccidiostatic drugs. Robenidine (alternately with Lerbec in farm A) was added to food in the first two farms, whilst Sulfatyf mixed with water was given once after weaning in farm C. A total of 203 individual faecal samples from females of breeding stock, and 133 pooled samples from young animals, were collected on an annual cycle during 2007-2008 (February-January), and analyzed according to a modified concentration McMaster method. Coccidians were identified based on sporulated oocysts. A number of coccidian species (Eimeria perforans, E. media, E. magna, E. irresidua, E. exiqua, E. coecicola, and E. piriformis) were observed in all farms. The most pathogenic species--E. intestinalis was found both in farm A and B, whereas E. flavescens and E. stiedae--only in the former. The level of infection was high, especially in young rabbits, with the prevalence of 94.9 to 100% and mean intensity from 11,161 to 28,871 oocysts per 1 g of faeces (OPG) in a particular warren. The highest intensity of infection was observed in May, when the mean output increased to 29,454, 56,952, and 23,815 OPG in warrens A, B, and C, respectively. A nematode, Passalurus ambiguus, was detected in all searched farms, with the prevalence from 14.1% to 27.5%, depending on a farm. The species was more often seen in the first part of year. The other helminths (Trichostrongylus retortaeformis, Graphidium strigosum, and Trichuris leporis) were found only in rabbits of warren C. In this warren, the forage of farm origin was suggested to be prepared in a proper way in order to protect it from nematode transmission. The presence of coccidia and their specific composition has been continuously monitored in all farms, to estimate the efficiency of prophylactic measures undertaken.