Biomedical subjects
Publications and source records attributed to R Gothe.
This paper reports on a case of hepatozoonosis of a dog imported from Italy to Germany being additionally infected with Ehrlichia canis and Babesia canis. Furthermore, a survey of the epidemiology of the Hepatozoon canis infection is presented.
Between June 1993 and May 1996 infections with filariae were diagnosed in 80 dogs. Five animals were infected with Dirofilaria repens and three other dogs with Dipetalonema reconditum. One of the D. reconditum positive dogs was also infected with Dirofilaria immitis. An epidemiological analysis of the cases was possible for three D. repens and two D. reconditum infected dogs. Two of the dogs with D. repens infections had been imported from Italy or Greece, the third dog had been taken by its owner to Hungary and former Yugoslavia. The dogs infected with D. reconditum were imported from Corse or Spain. Regarding the other 72 dogs with filariae, 45 animals were infected with D. immitis. For 27 dogs being negative in the D. immitis ELISA, microfilariae have been demonstrated. However, a histochemical species differentiation of the microfilariae was not possible because fresh blood smears were not available.
The influence of optical radiation on the emigration of third stage larvae out of faeces was investigated by exposing faeces containing infective larvae of Oesophagostomum quadrispinulatum to broad-band radiation of a sun-simulating wavelength spectrum corresponding to a sunny day, a cloudy day, dawn, and a full-moon night, as well as to monochromatic radiation of different wavelength spectrum at dawn and to complete darkness. It was demonstrated that third stage larvae of O. quadrispinulatum were able to differentiate between daylight and darkness responding to different irradiances with very high emigration rates at irradiances corresponding to dawn, and significantly lower emigration rates corresponding to full-moon light, and darkness as well as a cloudy and sunny day. Infective larvae reacted to monochromatic radiation of different wave-length spectrum at dawn and showed significantly higher emigration rates at the violet, green, yellow, and red light wavelength compared to darkness.
In this epidemiological study 127 horses from five breeding farms in Upper Bavaria were included. The horses were coproscopically examined in intervals of four weeks over a 16-month period. Since 1992 in all farms regular prophylactic treatments with anthelmintics have been carried out. In 127 horses at least five species were established, such as Parascaris equorum, Anoplocephala perfoliata, Gasterophilus intestinalis and small strongyles, whose third stage larvae were characterized by eight or twelve intestinal cells. Infections with small strongyles occurred most frequently, followed by G. intestinalis, A. perfoliata and P. equorum. Seven horses excreted eggs of P. equorum, three yearlings, and a two, four, five and seven year old animal, each. 113 of the 127 examined horses showed infections with strongyles, hence, almost all animals of the farms I-V. The evaluation of horses with strongyle infections as regards to the frequency of the coproscopically established eggs revealed a high incidence independent of age. The maximal epg-values showed no obvious age-dependent differences varying between < or = 67 and 3733. The horses excreted strongyle eggs with epg-values of > or = 333 predominantly during the summer. With an epg-value of > or = 333, independently of age the 23 horses treated with Ivomec-P as well as 20 of the 24 horses given Banminth remained coproscopically negative three to four weeks after treatment. The animals treated with Rintal or Panacur continued to excrete strongyle eggs three to four weeks following the anthelmintic application. The use of anthelmintics in horses with epg-values < 333 revealed analogous results. Infections with A. perfoliata were established in all farms, altogether in 32 horses independently of the age of the animals. Eggs of G. intestinalis have been observed only in two farms, but almost in all horses there.
During the period of January 1995 to January 1997, Babesia canis infections were diagnosed in 127 dogs, 65 of them had stayed in foreign countries where Dermacentor reticulatus is endemic, namely France, Austria and Hungary, or in the area Offenburg/Kehl/Freiburg i. Breisgau (Germany). Two dogs being positive for Babesia never had left Germany before and had not been in the region Offenburg/Kehl/Freiburg i. Breisgau. Concurrent tick infestations were reported for all of the 67 dogs. For 10 dogs which had travelled to Hungary and France the ticks were diagnosed as D. reticulatus. In Germany, ecological conditions are suitable for D. reticulatus and Babesia canis. Therefore, as a consequence of the spreading of these parasites the emergence of new endemic foci has to be expected.
In this epidemiological study 37 foals and mares were included, which have been coproscopically examined in regular intervals over a period lasting up to 13 months. The animals derived from nine breeding farms. In three of these farms no anthelmintics were used before this investigation, whereas in six farms at least three years before regular prophylactic treatments with anthelmintics have been carried out. This investigation revealed no differences in the species spectrum of endoparasites as well as in the incidence of infections as regards to the breeding farms with and without anthelmintic prophylaxis, however, significant differences between foals and mares. At least nine species were established in foals, Strongyloides westeri in 54.1% of the animals, Parascaris equorum in 64.9%, small strongyles, whose third stage larvae showed either eight or 12 intestinal cells, in 83.8%, Anoplocephala perfoliata in 16.2%, Eimeria leuckarti in 64.9%, Giardia in 5.4%, Cryptosporidium parvum in 2.7% and Gasterophilus intestinalis in 21.6%. Parasitic infections with two or more species were found in 83.8% of the foals. The species spectrum of endoparasites in mares from breeding farms without anthelmintic prophylaxis consisted of at least three species of small strongyles, whose third stage larvae were characterized by eight, 12 or 16 intestinal cells. In mares from breeding farms practising regular anthelmintic prophylaxis, however, at least seven species were ascertained, the same small strongyles, P. equorum, A. perfoliata, E. leuckarti and G. intestinalis.
Dermacentor reticulatus and D. marginatus, two ixodid tick species occurring in France and Germany, exhibit morphologically overlapping phenotypes. The results of sequence analyses of the hypervariable rDNA gene region ITS 2 do not support conspecifidity. As in France, D. reticulatus has to be characterized as an epidemiologically effective vector of Babesia canis in Germany as well, with the endemic area being located at Kehl/Offenburg/Lahr/Emmendingen/Freiburg in Breisgau. Ecological investigations indicate that a spreading of D. reticulatus and, as a possible consequence, that of B. canis in Germany has to be expected.
In this epidemiological study of endoparasites 37 donkeys and 23 horses were included, which were examined coproscopically in regular intervals over a 15 month period. The animals derived from ten farms, in which regular prophylactic treatments with anthelmintics had been practiced at least for two years before this investigation. This study revealed the presence of at least twelve parasite species in donkeys, Eimeria leuckarti, Gasterophilus intestinalis, Fasciola hepatica, Anoplocephala perfoliata, Strongyloides westeri, Parascaris equorum, Dictyocaulus arnfieldi, Trichostrongylus axei and small strongyles, whose third stage larvae were characterized by eight, twelve, 16 or 18 intestinal cells. At least four parasite species were established in horses, E. leuckarti, G. intestinalis, P. equorum and small strongyles, whose third stage larvae were provided with eight intestinal cells. Infections with E. leuckarti, S. westeri and P. equorum were encountered in foals only and with D. arnfieldi in 16.2% of the donkeys. Incidences for small strongyles were highest, exhibiting neither age- and farm-dependent nor host species-dependent differences and amounting to 91.9% in donkey and 86.6% in horses. Considering all donkeys and horses, 35.1% and 43.5%, respectively, were infected at least with two, and 29.7% and 4.3%, respectively, with three parasite species. The species composition of the endoparasite fauna was always dominated by small strongyles. This field study indicates that the species composition of the endoparasite fauna in comparison to former investigations has not or only slightly changed in spite of widespread use of broad-spectrum anthelmintics for years. In addition, it has to be considered that donkeys continue to act as reservoir of D. arnfieldi and as source of infection for horses.
This paper reports on a case of cutaneous myiasis due to Cordylobia anthropophaga in a dog imported from Cameroon to Germany. An account is given of the biology and ecology of this skin maggot fly as well as the clinics, diagnosis and treatment of the cutaneous myiasis are reviewed.
In hair samples from the accompanying equipment of a human mummy preserved in glacial ice in South Tyrol for more than 5000 years, numerous remains of insects were found. These fragments corresponded in form, size and structural organization to the features of the deer ked, Lipoptena cervi. Considering the biology and ecology of L. cervi with regard to the finding place of the mummy at an altitude of 3210 m above sea level in a glacier it is concluded that the deer keds invaded the equipment before and not after the death of the Stone Age man.
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Behavioural investigations into the perception and differentiation of coloured objects by unfed adult Hyalomma truncatum ticks revealed that silhouettes of blue, green, red and yellow colour, under illumination by a sun-simulating waveband spectrum, are perceived by the ticks and responded to equally by a directed response. Two green or dark grey rectangles each with a luminance contrast ratio of 5:1 against the white wall of the test arena in combination with an overlapping, equally sized dark grey or green target were consistently reached by ticks in a ratio of 2:1. Since the outer targets were occupied by the double number of ticks compared with the central silhouette this shows that the response is independent of the colour of the object. Investigations into target perception under monochromatic radiation of different wavelength ranges which were evenly adjusted in their irradiances revealed that ticks responded equally to a black target irradiated by blue, green, yellow and red light of wavelengths 428-472, 517-563, 549-591 and 606-654 nm, respectively. These results indicate the lack of true colour vision in H. truncatum.
Under controlled test conditions, unfed male and female Hyalomma truncatum ticks exhibited a positive scototaxis to stationary, two-dimensional targets. Upright-positioned rectangles were the most attractive targets. The attractiveness of these targets increased with their size. Significantly more ticks responded scototactically positively to the targets under a luminance contrast ratio of 5:1, as compared with other luminance contrast ratios. Targets with an elevation angle of 13 degrees were occupied more frequently than objects with higher elevation angles. Scototaxis was the same towards a stationary and a sinusoid oscillating target. When an upright-positioned rectangle was combined with a CO2 gradient, the number of ticks that migrated into the CO2 gradient and contacted the target did not increase significantly. The interval between exposure and first locomotion of the ticks, however, was significantly shorter under the influence of a CO2 gradient than in all other experiments without a CO2 gradient. A temperature gradient simulating a natural host (cattle) did not alter the scototaxis. The results of these investigations suggest that the positive scototaxis exhibited by adult H. truncatum ticks is not likely to be part of their appetence behaviour but rather searching behaviour to find adequate protection from harsh climatic conditions.
The species of single tick eggs, larvae and nymphs was determined by PCR amplification and characterization of the hypervariable, second transcribed spacer (ITS2) of the multicopy ribosomal RNA gene (rDNA). Engorgement of larvae and nymphs did not preclude species identification. The method is generally applicable for ixodid and argasid ticks and can be used for epidemiological studies requiring the identification of individuals from pre-adult stages.
International Journal for Parasitology 25: 1413-1419. Dermacentor reticulatus and D. marginatus exhibit overlapping phenotypes. The possibility of conspecificity was investigated on the nucleotide level by comparing DNA sequences of the second internal transcribed spacer (ITS 2) of the rDNA gene. The inter-specific polymorphism was more than 20-times greater than the intra-specific polymorphism of 3 D. reticulatus strains of different geographic origins. Furthermore, the degree of polymorphisms between D. reticulatus and D. marginatus was found to be of the same order of magnitude as that between D. andersoni and D. variabilis, for which separate species status is accepted. These genomic findings do not support a possible conspecificity of D. reticulatus and D. marginatus.
Continuing the studies on photoaffinity labelled analogues of the peptide hormone bradykinin (BK), several labelled antagonists were synthesized and characterized regarding their biological activities on rat uterus (RUT) and guinea pig ileum (GPI). The photoreactive amino acid p-benzoyl-phenylalanine (Bpa) was incorporated in potent, iodinated BK analogues at positions -2, -1, 0 and 7. The newly synthesized BK antagonists were derived from HOE 140 ([DArg0, Hyp3, Thi5, D-Tic7, Oic8]-BK) or [D-Phe7]-BK. Because the application of Bpa requires an additional group for the introduction of 125I, iodinated tyrosine was inserted at different positions as a model for radioiodination. Suitable positions for incorporation of tyrosine residues are -1, 0, 3 and 7, whereas the compound with 3-I-Tyr at position 4 had only a low biological activity. The antagonists obtained by modification of HOE 140 generally retained a high antagonistic potency. In this group [D-Bpa-2, 3-I-D-Tyr-1, D-Arg0, Hyp3, Thi5, D-Tic7, Oic8]-BK (pA2 values 8.06 on RUT and 8.15 on GPI) and [Bpa-1, D-Arg0, 3-I-Tyr3, Thi5, D-Tic7, Oic8]-BK (pA2 values 7.55 on RUT and 8.07 on GPI) belong to the most active compounds. The incorporation of D-Bpa at position 7 also resulted in potent analogues. The antagonists [3-I-Tyr-1, D-Arg0, D-Bpa7]-BK (pA2 on RUT 7.69) and [3-I-Tyr-1, D-Arg0, D-Bpa7, Oic8]-BK (pA2 on GPI 7.53) are an alternative to the N-terminal modified HOE 140 analogues. Compounds with D-Bpa7 act as pure competitive antagonists, whereas the HOE 140 derivatives show a mixed antagonism. The comparison of the results between photoaffinity labelled agonists and antagonists suggests that modifications in the series of BK antagonists were better tolerated.
Larvae of Dermacentor reticulatus hatched at a temperature range of 20-34 degrees C, but a high egg hatch success of > 90% was only achieved at 20 degrees C and 27 degrees C and 100% r.h. The developmental capability of the eggs at low or freezing temperatures persisted up to 3 weeks at -10 degrees C and up to 8 weeks at 5 degrees C. The 50% mortality period of unfed larvae and nymphs increased with rising humidity and was longest at 5 degrees C and 100% r.h., amounting to 83.5 days for larvae and 108 days for nymphs. Engorged larvae and nymphs only moulted in the temperature range of 10-27 degrees C. The percent moulting success was low at 10 degrees C and increased with rising ambient humidity at 20 degrees C and 27 degrees C reaching more than 90% at 100% r.h. After incubation at low or freezing temperatures and subsequent transfer to 20 degrees C and 100% r.h. engorged larvae did not moult after exposure to -10 degrees C, but they tolerated 0 degrees C and 5 degrees C up to 3 and 10 weeks, respectively, and developed into nymphs. Engorged nymphs moulted into adults even after preceding incubation at -10 degrees C, their metamorphosis capability persisted for a maximum of 4 and 17 weeks at 0 degrees C and 5 degrees C, respectively.
In this epidemiological survey 30 foals and their mares from seven breeding farms were investigated. Six farms used wide spectrum anthelmintics strategically at least for three years, on one farm no anthelmintic prophylaxis was practiced. Excretion of P.-equorum-eggs occurred in all breeding farms and in 80% of the foals, but in only one mare. In foals infection with roundworms was detected at the earliest 85 days post partum. Before first shedding of P.-equorum-eggs wide spectrum anthelmintics had been administered to two and to one foal(s) one and two times, respectively, to four animals three times and to one foal each four, five, six and seven times. After metaphylactic use of wide spectrum anthelmintics in the control of an infection with roundworms or other helminths, eggs of P. equorum were found in one foal already 12, 17, 54, 55, 70 and 71 days after treatment with Ivomec-P each and 65 days after use of Panacur in one foal. After application of Banminth roundworm eggs were detected 12, 27, 45, 47, 49 and 62 days in one foal each and 19 and 56 days in two foals each. In eight foals each P.-equorum-eggs were noticed 72 and 196 days after anthelmintic treatment.