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Biomedical subjects

D Mehlitz

Publications and source records attributed to D Mehlitz.

At least 55 records · Page 3Linked to original sources
PubMed1979

Trypanosome infections in domestic animals in Liberia.

In 5 domestic animal species of the Liberian rain forest, investigations were done on the infection rates with trypanosomes of the subgenera Nannomonas, Duttonella and Trypanozoon and on possible reservoir hosts for Trypanosoma (T.) brucei gambiense. Serological screening (indirect fluorescent antibody test) revealed that infection rates with Trypanosoma spp. were in N'Dama cattle 80.4%, in pigs 76.0%, in dogs 48.5%, in goats 35.1% and in sheep 28.1%. In N'Damas, antibodies to T. (N.) congolense and to T. (D.) vivax predominated and were distributed homogeneously; in pigs, antibodies to T. (N.) congolense were found most frequently. In dogs, antibodies to T. (N.) congolense and to T. (T.) b. brucei, and in goats and sheep antibodies to all 3 species were distributed homogeneously. Strong serological reactions (titres greater than 1:320) to T. (T.) b. brucei antigen were found most frequently in pigs (20.0%), in cattle (9.8%) and in dogs (9.5%). As suspicious reservoir hosts for T. (T.) b. gambiense, pigs (117) and dogs (105) were examined parasitologically in order to isolate Trypanozoon stocks for further infraspecific characterization. 56.4% of the pigs (14.5% Trypanozoon, 23.1% mixed Trypanozoon/Nannomonas, 18.8% Nannomonas), and 38.2% of the dogs (2.9% Trypanozoon, 14.3% mixed Trypanozoon/Nannomonas, 21.0% Nannomonas) were found to be infected. The sensitivities of the thick smear, the haematocrit centrifugation technique and the animal inoculation using Mastomys natalensis were described. 32 trypanosome stocks containing Trypanozoon were stabilized.

Animals↗
PubMed1978

Evaluation of an indirect fluorescent antibody test, enzyme-linked immunosorbent assay and quantification of immunoglobulins in the diagnosis of bovine trypanosomiasis.

An indirect fluorescent antibody test (IFAT), a microscale version of the enzyme-linked immunosorbent assay (microELISA) and determination of IgM levels in serum were assessed for their comparative diagnostic value in the detection of bovine trypanosomiasis. Serum samples from drug-treated N'dama cattle and untreated N'dama and Zebu cattle from Liberia were examined for the presence fo antibodies to trypanosomes. In the untreated Zebu cattle, infections with T. vivax predominated and the prevalence of infection was higher than that found in untreated N'damas in which infections with T. congolense predominated. The proportion of animals which showed serological evidence of trypanosomiasis in the untreated Zebus was slightly higher than that found in the untreated N'damas. The prevalence of infection was low in N'dama cattle which had been treated with diminazene aceturate and homidium chloride but 50% of the animals showed serological evidence of trypanosomiasis. More serologically positive animals were detected by microELISA than IFAT, but both tests were equally sensitive in detecting antibodies in cattle in which trypanosomes were demonstrated by examination of peripheral blood. With both IFAT and microELISA it was necessary to carry out tests using antigens prepared from T. brucei, T. vivax and T. congolense in order to detect all serologically positive animals. Increases in serum IgM occurred in both N'dama and Zebu cattle but the levels were raised in only approximately half of the known infected animals. Overall, more animals gave positive reactions with IFAT and microELISA than showed raised IgM levels.

Animals↗
PubMed1978

[Investigations on the susceptibility of Mastomys natalensis to Trypanosoma (trypanozoon) brucei gambiense (author's transl)].

Mastomys natalensis ("redeyed variant") proved to be as susceptible as suckling rats to infections with Trypanosoma (Trypanozoon) brucei gambiense (14 passages after isolation). The susceptibility of M. natalensis and rats was significantly higher than that of mice. After 21 further passages the T. (T.) b. gambiense strain was fully adapted to M. natalensis. Polymorphic trypanosome strains could be isolated from pigs and dogs in Liberia using M. natalensis as recipient rodents. Some of these strains were examined for their sensitivity to human plasma in the "blood incubation infectivity test" (BIIT) using M. natalensis as well. 6 strains were highly resistant resp. subresistant to human plasma and can be regarded as potentially infective (T. (T.) b. gambiense) for man. Referring to the investigations 1.) on the susceptibility, 2.) the isolation of trypanosome strains of the subgenus Trypanozoon from animal and 3.) the biological differentiation of these strains in the BIIT, M. natalensis can be regarded as suitable experimental animals for field and laboratory studies.

Animals↗
PubMed1978

Investigations on the prevalence of trypanosome carriers and the antibody response in wildlife in Northern Botswana.

605 buffalo, 60 lechwe, 23 kudu, 23 impala, 15 tsessebe, 22 sable and two reedbuck from Northern Botswana were examined for trypanosome infections by serological and/or parasitological means. The indirect fluorescent antibody test (IFAT), the haematocrit centrifugation technique (HCT) and rodent subinoculation were used. The overall prevalence of patent infection with trypanosomes in buffalo, lechwe and reedbuck was 15,7%. In the case of buffalo and lechwe it was possible to classify their origin into high and low tsetse fly density areas. Serological and parasitological results showed a significantly higher prevalence of infections in areas with a high fly density. Buffalo showed a predominance of infections with Trypanosoma (Duttonella) vivax and T. (Nannomonas) congolense, while in lechwe infections with T. (Trypanozoon) brucei were as frequent. Strains of T. (T.) brucei isolated from buffalo, unlike those from lechwe, failed to infect rodents, 6 strains from lechwe proved sensitive to human serum (Blood Incubation Infectivity Test). Parasitological positive cases, antibody response and the age of buffalo were correlated. The number of patent infections in animals over one year rose to a peak at the age of 2 1/2 years and dropped steadily in the older buffalo. The frequency of positive antibody titres and their levels also increased after the first years of age, reached its peak at the age of four years an then persisted for the rest of the animals' life. Serological tests carried out on serum samples of the remaining species showed that kudu were more frequently infected than impala, tsessebe or sable.

Animal Population Groups↗
PubMed1978

The identification of Trypanosoma brucei gambiense in Liberian pigs and dogs by isoenzymes and by resistance to human plasma.

29 Trypanozoon stocks from Liberian pigs and dogs were screened for human plasma resistance and electrophoretic isoenzyme patterns of eleven enzymes. Two stocks from pigs were found both to be resistant to human plasma and to have an isoenzyme marker, a slow alanine aminotransferase (ALAT) pattern, previously found only in Trypanosoma brucei gambiense from man. This constitutes evidence that the pig is a reservoir of human trypanosomiasis in West Africa. The T.b.gambiense ALAT was also found in stocks from 5 other pigs and a dog, but none of these stocks was resistant to human plasma; conversely, 9 further isolations from pigs and 2 from dogs were plasma resistant but did not have the T.b.gambiense ALAT. The lack of correspondence between the two characteristics is discussed. A T.b.gambiense stock from man in Zaire had the ALAT pattern characteristic of T.b.gambiense from Senegal and Nigeria, together with the ASAT triplet found in most T.b.gambiense stocks. Peptidase polymorphism was shown in trypanosomes for the first time.

Alanine Transaminase↗
PubMed1977

[Extravascular localization of Trypanosoma vivax in cattle (author's transl)].

In 2 cattle experimentally infected with Trypanosoma vivax, strain EATRO 1695, trypanosomes were found in the marginal sinus of one of several lymph nodes examined. One animal showed trypanosomes in a small focus in the interstitial tissue of the heart. It is concluded that Trypanosoma vivax can not be regarded as a strict plasma parasite.

Animals↗
PubMed1976

[Experimental Trypanosoma infections in Cameroon dwarf goats: histopathological observations (author's transl)].

14 Cameroon Dwarf goats were experimentally infected with Trypanosoma (Duttonella) vivax, T. (Nannomonas) congolense, and T. (Trypanozoon) brucei. Infection with T. burcei caused death of the animals within 45-201 days. All goats which died following T. brucei-infection showed characteristic mononuclear cell infiltrations in brain and heart, most of them showed infiltrations in skin (eye lids), sceletal muscles, kidneys, fat and connective tissue as well. Infections with T. vivax and T. congolense produced no clinical signs and very little histological alterations. Animals infected with T. congolense or T. brucei for more than 5 months showed amyloid deposits in their livers, spleens and kidneys.

Amyloidosis↗
PubMed1975

[Serological studies on subgenus-differentiation and persistence of antibodies following infections with Trypanosomes (author's transl)].

10 cattle were infected or superinfected with Trypanosoma species of the subgenera Nannomonas (T. congolense), Duttonella (T. vivax) and Trypanozoon (T. brucei) respectively. The complement fixation test (CTF) and the indirect fluorescent antibody test (IFAT) were employed to investigate the possible differentiation of subgenera by serological methods and the persistence of antibodies. The serological results were compared with those of parasitological and hematological findings. After monospecific infections and most superinfections a subgenus differention of antibodies was possible with the IFAT, but not with the CFT. Specific antibodies were demonstrated 285 days after the last parasites were seen.

Animals↗