Sven Klimpel

First occurrence of Culicoides obsoletus-transmitted Bluetongue virus epidemic in Central Europe

In August 2006, Bluetongue virus disease (BTD) was detected for the first time in the Netherlands, Belgium, Germany and Northern France. Serological tests as well as reverse transcriptase polymerase chain reaction (RT-PCR) proved the occurrence of Bluetongue virus (BTV) in diseased sheep and cattle, and the virus was identified as serotype 8. Therefore, the search for possible vectors was immediately initiated in the outbreak region in Germany. Traps with automatically regulated ultraviolet light lamps were placed at two different farms with sero-positive cattle, and insect monitoring was done from August 2006 until January 2007. The caught arthropods were weekly determined, and it could be observed that midges of the dipteran family Ceratopogonidae occurred in large numbers, sometimes representing up to 40% of all individuals. The microscopical analysis of the wing morphology showed that the species (complex) Culicoides obsoletus was most abundant covering about 97% of the analysed midges. On the second place ranged C. pulicaris, while C. nubeculosus and C. festivipennis were found only as single individuals. Fed and unfed females were separated, sent to the National Reference Laboratory for Bluetongue disease (Friedrich-Loeffler-Institut, Isle of Riems, Germany) and investigated with a BTV-8-specific real-time RT-PCR. It could be demonstrated that at both farms both fed and unfed C. obsoletus were tested positive for BTV-8 genomes, while none of the other species scored positive. This finding strongly supports that the BTD-epidemic, which reached in the meantime wide regions of North Rhine–Westphalia in Germany and of the neighbouring countries with several hundreds of affected farms, is initiated by virus transmission during the blood meal of midges of the C. obsoletus complex. Since they were captured still at the 21st of December close to cattle with clinical signs, it must be feared that BTV-8 is now established in Central Europe, where it had been absent until now.

Pilot study on synanthropic flies (e.g. Musca, Sarcophaga, Calliphora, Fannia, Lucilia, Stomoxys) as vectors of pathogenic microorganisms

In the present study, different fly species were associated with foodborne and other pathogens. Wild synanthropic flies belonging to 12 species of 12 genera were caught for the isolation and identification of microorganisms, which might have been possibly transmitted by these flies. Trapping of flies was done at different domestic animal related places (dog pound, poultry house, cattle barn, horse stable, pigpen). All 56 individual flies were shown to be carriers of multiple species of microorganisms. Furthermore, the capacity for the flies to act as vectors was demonstrated by successful transfer of the microorganisms from live flies to blood agar plates. Potentially pathogenic and several non-pathogenic microorganisms were found. Among them, a series of pathogenic Escherichia coli strains (EAEC, EPEC, ETEC) was identified. This is the first study to clearly demonstrate the potential of these flies as vectors for the transmission of pathogenic microorganisms.

The life cycle of Anisakis simplex in the Norwegian Deep (northern North Sea)

Copepoda (Calanus finmarchicus n=1,722, Paraeuchaeta norvegica n=1,955), Hyperiidae (n=3,019), Euphausiacea (Meganyctiphanes norvegica n=4,780), and the fishes Maurolicus muelleri (n=500) and Pollachius virens (n=33) were collected in the Norwegian Deep (northern North Sea) during summer 2001 to examine the importance of pelagic invertebrates and vertebrates as hosts of Anisakis simplex and their roles in the transfer of this nematode to its final hosts (Cetaceans). Third stage larvae (L3) of A. simplex were found in P. norvegica, M. muelleri and P. virens. The prevalence of A. simplex in dissected P. norvegica was 0.26%, with an intensity of 1. Prevalences in M. muelleri and P. virens were 49.6% and 100.0%, with mean intensities of 1.1–2.6 (total fish length ≥6.0–7.2) and 193.6, respectively. All specimens of C. finmarchicus and M. norvegica examined were free of anisakid nematode species and no other parasites were detected. P. norvegica, which harboured the third stage larvae, is the obligatory first intermediate host of A. simplex in the investigated area. Though there was no apparent development of larvae in M. muelleri, this fish can be considered as the obligatory second intermediate host of A. simplex in the Norwegian Deep. However, it is unlikely that the larva from P. norvegica can be successfully transmitted into the cetacean or pinniped final hosts, where they reach the adult stage. An additional growth phase and a second intermediate host is the next phase in the life cycle. Larger predators such as P. virens serve as paratenic hosts, accumulating the already infective stage from M. muelleri. The oceanic life cycle of A. simplex in the Norwegian Deep is very different in terms of hosts and proposed life cycle patterns of A. simplex from other regions, involving only a few intermediate hosts. In contrast to earlier suggestions, euphausiids have no importance at all for the successful transmission of A. simplex in the Norwegian Deep. This demonstrates that this nematode is able to select definite host species depending on the locality, apparently having a very low level of host specificity. This could explain the wide range of different hosts that have been recorded for this species, and can be seen as the reason for the success of this parasite in reaching its marine mammal final hosts in an oceanic environment.

The efficacy of neem seed extracts (Tre-san®, MiteStop®) on a broad spectrum of pests and parasites

The paper summarizes the acaricidal and insecticidal effects of a patented neem seed extract when diluted 1:10 with shampoo or 1:20, 1:30, 1:33, 1:40, respectively, 1:66 with tap water. It was shown that a broad range of pests and parasites, such as house dust mites, poultry mites, harvest mites, Ixodes and Rhipicephalus ticks, cat fleas (adults, larvae), bed bugs (all stages), head lice and mallophaga, cockroaches (genera Blatta, Blattella, Gomphadorhina), raptor bugs (Triatoma), and even food-attacking beetle (Tenebrio molitor) might be controlled with this extract, which is available as Tre-san® (against house dust mites) and MiteStop® (against mites, ticks, insects of any kind) to become water diluted or as Wash Away Louse® or Picksan LouseStop® being diluted in a shampoo. Tests on skin compatibility proved that there are no skin irritations during or after use. However, some target species are less sensible (beetles, Triatoma stages, fly maggots), while the specimens of the other species cited above were successfully killed even at low concentrations of the extract.

Life cycle strategy of Hysterothylacium aduncum to become the most abundant anisakid fish nematode in the North Sea

The present study demonstrates the influence of physical systems (mixed and stratified waters) on the occurrence and distribution of the anisakid nematode Hysterothylacium aduncum in commercially important gadiform fish species from the central and northern North Sea. Stratified waters are essential in structuring marine food webs and are therefore also important for the transfer of fish parasites to their host species. During two research cruises in 2001, 308 haddocks (Melanogrammus aeglefinus) and 203 whitings (Merlangius merlangus) were caught in the central and northern North Sea and were examined for anisakid nematode parasites and food composition. Additionally, the most abundant pelagic invertebrates, hyperiid amphipods, of the investigated area were sampled and examined with regard to their parasite infestation rates. The influence of stratified waters on the infestation of the gadiform fish species by H. aduncum was shown by ecological and parasitological investigations. In stratified areas haddocks and whitings feed specifically and invariably on pelagic hyperiids. The number of ingested hyperiids in these areas was in both fish species correlated with infestation rates of H. aduncum. Therefore, hyperiids were identified as the obligatory intermediated host of H. aduncum, since these crustaceans carried high numbers of nematode larvae in their haemocoel. The results of the present study demonstrate that haddocks and whitings from the stratified waters are highly parasitised, both in terms of the numbers of individuals of larval and adult stages of H. aduncum.

Adaptive Radiation within Marine Anisakid Nematodes: A Zoogeographical Modeling of Cosmopolitan, Zoonotic Parasites

Parasites of the nematode genus Anisakis are associated with aquatic organisms. They can be found in a variety of marine hosts including whales, crustaceans, fish and cephalopods and are known to be the cause of the zoonotic disease anisakiasis, a painful inflammation of the gastro-intestinal tract caused by the accidental consumptions of infectious larvae raw or semi-raw fishery products. Since the demand on fish as dietary protein source and the export rates of seafood products in general is rapidly increasing worldwide, the knowledge about the distribution of potential foodborne human pathogens in seafood is of major significance for human health. Studies have provided evidence that a few Anisakis species can cause clinical symptoms in humans. The aim of our study was to interpolate the species range for every described Anisakis species on the basis of the existing occurrence data. We used sequence data of 373 Anisakis larvae from 30 different hosts worldwide and previously published molecular data (n = 584) from 53 field-specific publications to model the species range of Anisakis spp., using a interpolation method that combines aspects of the alpha hull interpolation algorithm as well as the conditional interpolation approach. The results of our approach strongly indicate the existence of species-specific distribution patterns of Anisakis spp. within different climate zones and oceans that are in principle congruent with those of their respective final hosts. Our results support preceding studies that propose anisakid nematodes as useful biological indicators for their final host distribution and abundance as they closely follow the trophic relationships among their successive hosts. The modeling might although be helpful for predicting the likelihood of infection in order to reduce the risk of anisakiasis cases in a given area.

The effects of different plant extracts on intestinal cestodes and on trematodes

In the present study, chloroform, aqueous, (polyethylene glycol/propylene carbonate) PEG/PC extracts were made from coconut, onion, garlic, fig, date tree, chicory, ananas, and cistrose. These extracts were tested in vivo and in vitro on their anthelmintic activity against cestodes (Hymenolepis diminuta, H. microstoma, Taenia taeniaeformis) and trematodes (Fasciola hepatica, Echinostoma caproni). In all in vitro tests, the target parasites died. It turned out that the treatment of mice and rats with a combination of onion and coconut extracts (with PEG/PC) eliminated all cestodes from their final hosts. In addition, the same composition was effective against the intestinal fluke E. caproni, but not against the liver fluke F. hepatica in the final host, while both worms were killed in vitro. Inoculation of fluids of coconut eliminated T. taeniaeformis tapeworms from naturally infected cats. This goal was not reached with oil of cistrose.

Anisakid Nematode (Ascaridoidea) Life Cycles and Distribution: Increasing Zoonotic Potential in the Time of Climate Change?

Parasitic nematodes are known as important pathogens that cause problems for human and animal health. Some of them naturally inhabit the marine environment, where they are widespread and can be found in a variety of different hosts. Food-borne zoonoses via aquatic animals are most often linked to anisakid nematodes of the genera Anisakis Dujardin, 1845, Contracaecum Railliet and Henry, 1912, and Pseudoterranova Mozgovoi, 1951. These are commonly found in the digestive tract of marine mammals, and infect aquatic invertebrates and vertebrates as intermediate hosts. The most widely distributed whale worms Anisakis spp. involve cetaceans as final and planktonic copepods, euphausiids, squids and teleosts as intermediate or paratenic hosts. Painful infections of the digestive tract in humans originate through consumption of raw or semi-raw fisheries products, for example fish and squid. Recent molecular studies revealed the existence of morphologically similar but genetically different cryptic species (‘sibling species’) within the anisakids. Among these, A. simplex (s.s.) is responsible for the highest number of recorded human infections. Molecular studies of Anisakis larvae from various parts of the world Oceans demonstrate an uneven species distribution, with A. simplex (s.s.) being limited to the northern hemisphere. Another species, A. typica, has not yet been connected to this disease, and seems to be restricted to the tropical regions. This chapter presents the present state of knowledge about this widespread group of fish parasites, including the importance as human pathogens, their life cycle biology, biogeography and phylogeny. The distribution of the currently recognized Anisakis species is summarized and combined with the number of known cases of human anisakiasis. We suggest that pathogenicity for humans is different among the Anisakis siblings, providing a possible explanation for uneven disease records worldwide. The possibility of a changing risk of anisakidosis in the time of climate change is discussed.

Parasites of two abundant sympatric rodent species in relation to host phylogeny and ecology

In the present study, two abundant sympatric rodent species (27 Apodemus flavicollis and 33 A. sylvaticus) were studied for their endo- and ectoparasite fauna. The rodents were trapped in Dormagen, a city in North Rhine–Westphalia, Germany. A total of 20 different parasites species were identified, 13 endoparasite (2 Digenea, 5 Cestoda and 7 Nematoda) and 7 ectoparasite (5 Insecta and 2 Arachnida) species. Thirteen parasite species were found inhabiting both rodent species. The predominant endoparasite species in both rodents was the nematode Pelodera strongyloides, followed by the nematode Heligmosomoides polygyrus and a Syphacia species. The flea Ctenophthalmus agyrtes was the dominant ectoparasite in both rodent species. A. flavicollis usually carried 1–7 ecto-/endoparasite species (mean 4.0), whereas A. sylvaticus were mostly infested with 1–9 (mean 4.4). The parasite diversity of A. flavicollis (H′ = 0.268, J = 0.097) was marginal lower in comparison to A. sylvaticus (H′ = 0.319, J = 0.110). The two rodent species examined show remarkable similarities in the composition of their endo- and ectoparasite fauna being directly related to their similar pattern of living in the investigated area.

Gastrointestinal and ectoparasites from urban stray dogs in Fortaleza (Brazil): high infection risk for humans?

Dogs are important definite or reservoir hosts for zoonotic parasites. However, only few studies on the prevalence of intestinal parasites in urban areas in Brazil are available. We performed a comprehensive study on parasites of stray dogs in a Brazilian metropolitan area. We included 46 stray dogs caught in the urban areas of Fortaleza (northeast Brazil). After euthanization, dogs were autopsied. Ectoparasites were collected, and the intestinal content of dogs were examined for the presence of parasites. Faecal samples were collected and analysed using merthiolate iodine formaldehyde concentration method. A total of nine different parasite species were found, including five endoparasite (one protozoan, one cestode and three nematode species) and four ectoparasite species (two flea, one louse and one tick species). In the intestinal content, 3,162 specimens of four helminth species were found: Ancylostoma caninum (prevalence, 95.7%), Dipylidium caninum (45.7%), Toxocara canis (8.7%) and Trichuris vulpis (4.3%). A total of 394 ectoparasite specimens were identified, including Rhipicephalus sanguineus (prevalence, 100.0%), Heterodoxus spiniger (67.4%), Ctenocephalides canis (39.1%) and Ctenocephalides felis (17.4%). In the faeces, intestinal parasites were detected in 38 stray dogs (82.6%), including oocysts of Giardia sp. (2.2%) and eggs of the nematode A. caninum (82.6%). Neither eggs nor larval stages of D. caninum, T. canis or T. vulpis were detected in dog faeces. Sensitivity of faecal examination for A. caninum was 86.4% (95% confidence interval, 72.0–94.3) but zero percentage for the other intestinal helminth species. Our data show that stray dogs in northeast Brazil carry a multitude of zoonotic ecto- and endoparasites, posing a considerable risk for humans. With the exception of A. caninum, sensitivity of faecal examination was negligible.