Infectivity and virulence of Trypanosoma evansi and Trypanosoma equiperdum Venezuelan strains from three different host species.

The infectivity and virulence of seven Trypanosoma evansi and Trypanosoma equiperdum Venezuelan strains isolated from horses, donkeys and capybaras were compared in a mouse model up to 41 days, for parasitemia, animal weight, survival rates, packed cell volume, haemoglobin and erythrocyte count. Two T. equiperdum strains and three of the T. evansi strains resulted in 100% mice mortality, while the two T. evansi donkey strains exhibited lower infectivity and mortality. T. equiperdum strains had shorter pre-patent periods (4 days) than the T. evansi strains (4-12 days). In terms of pathogenicity, only the T. evansi horse strain and the two capybara strains produced a significant decrease of the packed cell volume, in haemoglobin concentration and in red blood cell count. In contrast, the T. evansi donkey strains did not show any changes in the hematological parameters. From the seven variables studied, only pre-patent period, day of maximum parasitemia, day of first parasitemia peak and number of parasitemia peaks were statistically significant. Weight decrease was only observed in mice infected with the T. evansi horse strain. T. equiperdum strains showed the highest mice lethality (7% survival by day 8 post-infection) with no change in the hematological parameters. The three T. evansi horse and capybara strains showed 80%, 87% and 97% survival rates, respectively by day 12 post-infection. However, by day 20 post-inoculation all the mice infected with the T. evansi horse strain died, while 53% and 27% capybara strains infected survived. Whereas by day 40 post-infection, 53 and 73% of the mice infected with the T. evansi donkey strains had survived. These results demonstrate striking infectivity and virulence differences between Venezuelan T. evansi and T. equiperdum strains in NMRI mice and open new possibilities to characterize inter and intra-species variations that may contribute to the pathogenicity of these two species.

Trypanosoma vivax in water buffalo of the Venezuelan Llanos: An unusual outbreak of wasting disease in an endemic area of typically asymptomatic infections.

Trypanosoma vivax has been associated with asymptomatic infections in African and South American buffalo. In this study, T. vivax was analyzed in water buffalo (Bubalus bubalis) from Venezuela in a molecular survey involving 293 blood samples collected from 2006 to 2015 across the Llanos region. Results demonstrated constant infections (average 23%) during the years analyzed. In general, animals were healthy carriers of T. vivax with low levels of parasitemia and were diagnosed exclusively by TviCATL-PCR. However, an outbreak of severe acute infections mostly in dairy animals was reported during a prolonged drought affecting 30.4% of a buffalo herd (115 animals examined). During the outbreak, animals exhibiting anemia and neurological disorders developed fatal infections, and 7% of the herd died within nine months before treatment against trypanosomosis. Microsatellite locus genotyping (MLG) of T. vivax samples before and during the outbreak revealed similar genotypes, but outbreak isolates exhibited the most divergent MLG. Venezuelan samples from symptomless and sick buffalo did not share the MLGs previously detected in asymptomatic Brazilian buffalo. Trypanosoma evansi was not detected in the herd examined during the outbreak. However, as expected Babesia sp. (62.6%) and Anaplasma sp. (55.6%) infections were highly prevalent in asymptomatic buffalo in the studied areas. This is the first South American outbreak of highly lethal acute T. vivax infections in water buffalo. Our results suggest that chronically infected and asymptomatic buffalo living in areas of enzootic equilibrium can develop symptomatic/lethal disease triggered by stressful scarcity of green forage and water during long droughts, inappropriate management of herds and likely concomitant anaplasmosis and babesiosis. Altogether, these factors weaken buffalo immune defenses, allowing T. vivax to proliferate and, consequently, allowing for progression to wasting disease.

A nanotechnology based new approach for Trypanosoma evansi chemotherapy: In vitro and vivo trypanocidal effect of (-)-α-bisabolol.

The aim of this study was to evaluate the in vitro and in vivo susceptibility of Trypanosoma evansi to α-Bisabolol and solid lipid nanoparticles containing α-Bisabolol (SLN-B). In vitro, a trypanocidal effect of α-Bisabolol and SLN-B was observed when used at 0.5, 1 and 2% concentrations, i.e., the concentrations of 1 and 2% showed a faster trypanocidal effect when compared to chemotherapy (diminazene aceturate - D.A.). T. evansi infected mice were treated with α-Bisabolol and SLN-B at a dose of 1.0 mL kg-1 during seven days via oral gavage. In vivo, treatment with SLN-B, D.A. and D.A. associated with SLN-B were able to increase (p < 0.05) the pre-patent period and longevity when compared to positive control (infected and untreated animals), but showed no curative efficacy. T. evansi infected mice treated with D.A. associate with SLN-B, where a curative efficacy of 50% was found, a much better result when D. A and SLN-B were used alone (16.66%). In summary, the association with D. A + SLN-B can be used as an alternative to improve the therapeutic effectiveness of D.A., and for treatment of infected animals with T. evansi. Also, the nanotechnology associated with natural products arises an important alternative for the improve the trypanocidal action.

Temporal and spatial dynamics of trypanosomes infecting the brush-tailed bettong (Bettongia penicillata): a cautionary note of disease-induced population decline.

BACKGROUND: The brush-tailed bettong or woylie (Bettongia penicillata) is on the brink of extinction. Its numbers have declined by 90% since 1999, with their current distribution occupying less than 1% of their former Australian range. Woylies are known to be infected with three different trypanosomes (Trypanosoma vegrandis, Trypanosoma copemani and Trypanosoma sp. H25) and two different strains of T. copemani that vary in virulence. However, the role that these haemoparasites have played during the recent decline of their host is unclear and is part of ongoing investigation. METHODS: Woylies were sampled from five locations in southern Western Australia, including two neighbouring indigenous populations, two enclosed (fenced) populations and a captive colony. PCR was used to individually identify the three different trypanosomes from blood and tissues of the host, and to investigate the temporal and spatial dynamics of trypanosome infections. RESULTS: The spatial pattern of trypanosome infection varied among the five study sites, with a greater proportion of woylies from the Perup indigenous population being infected with T. copemani than from the neighbouring Kingston indigenous population. For an established infection, T. copemani detection was temporally inconsistent. The more virulent strain of T. copemani appeared to regress at a faster rate than the less virulent strain, with the infection possibly transitioning from the acute to chronic phase. Interspecific competition may also exist between T. copemani and T. vegrandis, where an existing T. vegrandis infection may moderate the sequential establishment of the more virulent T. copemani. CONCLUSION: In this study, we provide a possible temporal connection implicating T. copemani as the disease agent linked with the recent decline of the Kingston indigenous woylie population within the Upper Warren region of Western Australia. The chronic association of trypanosomes with the internal organs of its host may be potentially pathogenic and adversely affect their long term fitness and coordination, making the woylie more susceptible to predation.

Atypical human infections by animal trypanosomes.

The two classical forms of human trypanosomoses are sleeping sickness due to Trypanosoma brucei gambiense or T. brucei rhodesiense, and Chagas disease due to T. cruzi. However, a number of atypical human infections caused by other T. species (or sub-species) have been reported, namely due to T. brucei brucei, T. vivax, T. congolense, T. evansi, T. lewisi, and T. lewisi-like. These cases are reviewed here. Some infections were transient in nature, while others required treatments that were successful in most cases, although two cases were fatal. A recent case of infection due to T. evansi was related to a lack of apolipoprotein L-I, but T. lewisi infections were not related to immunosuppression or specific human genetic profiles. Out of 19 patients, eight were confirmed between 1974 and 2010, thanks to improved molecular techniques. However, the number of cases of atypical human trypanosomoses might be underestimated. Thus, improvement, evaluation of new diagnostic tests, and field investigations are required for detection and confirmation of these atypical cases.

Tripanosomiasis en el embarazo / Trypanosomiasis in pregnancy

OBJETIVO: describir la morbimortalidad materna y perinatal causada por la tripanosomiasis en las gestantes que asisten a control en el Servicio Prenatal de la Maternidad “Concepción Palacios” y al Hospital Central de Biscucuy. MÉTODOS: Se incluyó una muestra de 828 pacientes, 178 de la zona rural y 650 de la urbana. Se realizó la pesquisa para tripanosomiasis mediante prueba rápida y confirmación por serología, de las madres positivas para tripanosomiasis. Se tomó muestra de la sangre del cordón umbilical para determinar la transmisión congénita de la enfermedad. RESULTADOS: Fueron positivas para enfermedad de Chagas 6 pacientes, para una frecuencia global de 0,72 %. Cinco de las pacientes provenían de la zona rural (2,8.%) y una del medio urbano (0,15 %). Entre las 6 pacientes positivas, 83,3 % provenía de la zona rural y 16,7 % de la urbana. La serología de los recién nacidos fue positiva en cuatro casos del medio rural y un caso del medio urbano. La reacción en cadena de la polimerasa fue positiva en 2 de los 6 neonatos de madres con la enfermedad. Las pruebas parasitológicas fueron negativas en el 100.% de los neonatos en riesgo. CONCLUSIONES: La frecuencia de tripanosomiasis fue de 0,72 %. No hubo transmisión congénita de la enfermedad.

OBJECTIVE: to describe maternal and perinatal morbidity and mortality caused by trypanosomiasis in pregnant women attending prenatal control in the obstetric service of Maternidad “Concepcion Palacios” and Hospital Central de Biscucuy. METHODS: A sample of 828 patients was included from both areas, 178 in rural and 650 urban. Research was performed by rapid test for trypanosomiasis and confirmation by serology, from mothers positive for trypanosomiasis. Sample was taken from the umbilical cord blood to determine congenital transmission of the disease. RESULTS: Were positive for Chagas disease 6 patients, for an overall frequency of 0.72 %. Five of the patients were from rural areas (2.8 %) and in urban areas (0.15 %). Between 6 positive patients, 83.3 % came from rural and 16.7 % urban areas. The newborns serology was positive in four cases of rural and urban case. The chain reaction polymerase was positive in 2 of the 6 infants of mothers with the disease. Parasitological tests were negative in 100 % of infants at risk. CONCLUSIONS: The frequency of trypanosomiasis was 0.72 %. There was not congenital transmission of the disease.

The acute and sub-chronic exposures of goldfish to naphthenic acids induce different host defense responses.

Naphthenic acids (NAs) are believed to be the major toxic component in oil sands process-affected water (OSPW) produced by the oil sands mining industry in Northern Alberta, Canada. We recently reported that oral exposure to NAs alters mammalian immune responses, but the effect of OSPW or NAs on the immune mechanisms of aquatic organisms has not been fully elucidated. We analyzed the effects of acute and sub-chronic NAs exposures on goldfish immune responses by measuring the expression of three pro-inflammatory cytokine genes, antimicrobial functions of macrophages, and host defense after challenge with a protozoan pathogen (Trypanosoma carassii). One week after NAs exposure, fish exhibited increased expression of pro-inflammatory cytokines (IFNγ, IL-1ß1, TNF-α2) in the gills, kidney and spleen. Primary macrophages from fish exposed to NAs for one week, exhibited increased production of nitric oxide and reactive oxygen intermediates. Goldfish exposed for one week to 20 mg/L NAs were more resistant to infection by T. carassii. In contrast, sub-chronic exposure of goldfish (12 weeks) to NAs resulted in decreased expression of pro-inflammatory cytokines in the gills, kidney and spleen. The sub-chronic exposure to NAs reduced the ability of goldfish to control the T. carassii infection, exemplified by a drastic increase in fish mortality and increased blood parasite loads. This is the first report analyzing the effects of OSPW contaminants on the immune system of aquatic vertebrates. We believe that the bioassays depicted in this work will be valuable tools for analyzing the efficacy of OSPW remediation techniques and assessment of diverse environmental pollutants.

The potential impact of native Australian trypanosome infections on the health of koalas (Phascolarctos cinereus).

Whole blood collected from koalas admitted to the Australian Zoo Wildlife Hospital (AZWH), Beerwah, QLd, Australia, during late 2006-2009 was tested using trypanosome species-specific 18S rDNA PCRs designed to amplify DNA from Trypanosoma irwini, T. gilletti and T. copemani. Clinical records for each koala sampled were reviewed and age, sex, blood packed cell volume (PCV), body condition, signs of illness, blood loss, trauma, chlamydiosis, bone marrow disease, koala AIDS and hospital admission outcome ('survival'/ 'non-survival') were correlated with PCR results. Overall 73.8% (439/595) of the koalas were infected with at least 1 species of trypanosome. Trypanosoma irwini was detected in 423/595 (71.1%), T. gilletti in 128/595 (21.5%) and T. copemani in 26/595 (4.4%) of koalas. Mixed infections were detected in 125/595 (21%) with co-infections of T. irwini and T. gilletti (101/595, 17%) being most common. There was a statistical association between infection with T. gilletti with lower PCV values and body condition scores in koalas with signs of chlamydiosis, bone marrow disease or koala AIDS. No association between T. gilletti infection and any indicator of health was observed in koalas without signs of concurrent disease. This raises the possibility that T. gilletti may be potentiating other disease syndromes affecting koalas.

Susceptibility of mice to Trypanosoma evansi treated with human plasma containing different concentrations of apolipoprotein L-1.

The aim of this study was to test the susceptibility of mice to Trypanosoma evansi treated with human plasma containing different concentrations of apolipoprotein L-1 (APOL1). For this experiment, a strain of T. evansi and human plasma (plasmas 1, 2, and 3) from 3 adult males clinically healthy were used. In vivo test used 50 mice divided in 5 groups (A to E) with 10 animals in each group. Animals of groups B to E were infected, and then treated with 0.2 ml of human plasma in the following outline: negative control (A), positive control (B), treatment with plasma 1 (C), treatment with plasma 2 (D), and treatment with plasma 3 (E). Mice treated with human plasma showed an increase in longevity of 40.9 ± 0.3 (C), 20 ± 9.0 (D) and 35.6 ± 9.3 (E) days compared to the control group (B) which was 4.3 ± 0.5 days. The number of surviving mice and free of the parasite (blood smear and PCR negative) at the end of the experiment was 90%, 0%, and 60% for groups C, D, and E, respectively. The quantification of APOL1 was performed due to the large difference in the treatments that differed in the source plasma. In plasmas 1, 2, and 3 was detected the concentration of 194, 99, and 115 mg/dl of APOL1, respectively. However, we believe that this difference in the treatment efficiency is related to the level of APOL1 in plasmas.

Susceptibility of Trypanosoma evansi to human blood and plasma in infected mice.

Around 1900 Laveran and Mesnil discovered that African trypanosomes do not survive in the blood of some primates and humans. The nature of the trypanolytic factor present in these sera has been the focus of a long-standing debate between different groups. The aim of this study was to investigate the susceptibility of T. evansi isolates to therapy using human blood and plasma in experimentally infected mice. Forty-eight 2-month-old female mice (Mus musculus) were divided into six groups of eight animals per group (A, B, C, D, E and F). Plasma was obtained after blood collection in order to perform therapy. Animals from group A (positive control) were inoculated with T. evansi and treated with 0.2mL of saline solution. Animals from groups B and C were infected with the flagellate and received a curative treatment with 0.2mL of human blood (group B) and 0.2mL of human plasma (group C), 24h after infection. Animals from groups D and E received a prophylactic treatment with 0.2mL of human blood and 0.2mL of human plasma, respectively, 24h prior to the infection. Animals from group F (negative control) were not infected and received 0.2mL of saline solution. The four treatments (B, C, D and E) increased animals longevity when compared to group A. Prepatency period was longer in groups D (15 days) and E (37.7 days) under prophylactic immunotherapy. Moreover, no parasites were found in most of the animals 60 days post-inoculation (PI). Besides the longer longevity, treatments were capable of curing 50% of mice of group B, 37.5% of group C, 37.5% of group D and 25% of the animals from group E.

Infection by Trypanosoma vivax in goats and sheep in the Brazilian semiarid region: from acute disease outbreak to chronic cryptic infection.

A study was undertaken to investigate the role of Trypanosoma vivax in sheep and goat mortality and abortions in the Brazilian semiarid region, where outbreaks had been previously reported in bovines. For this purpose, 177 goats and 248 sheep (20% of herds) were randomly sampled on four farms in the State of Paraiba in May and October 2008. The animals were screened for trypanosomes by the buffy coat technique (BCT) and PCR. Infected animals, approximately 25% in both surveys, manifested apathy, pale mucous membranes, enlarged lymph nodes, weakness, weight loss, opacity of the cornea, blindness and abortion. However, the animals with acute and severe disease showing the highest levels of parasitemia and fever, which many times resulted in death, were only detected in the first survey. These severely diseased animals exhibited progressive weight loss and had the smallest packed cell volume (PCV) values. During survey 2, done in October 2008 on the same farms, only animals with low parasitemia and normal temperatures, PCV values and body weights were detected. Therefore, animals that spontaneously recovered from acute infection developed chronic and asymptomatic disease. This finding demonstrated for the first time that sheep and goats, which are the most important livestock in the semiarid region of Brazil, may be severely injured by T. vivax infection and also play a role as asymptomatic carriers and important sources of T. vivax to ruminants in general.

Mortality of domesticated java deer attributed to Surra.

This paper reports an outbreak of trypanosomiasis due to Trypanosoma evansi in Java deer (Cervus timorensis) on a government deer farm in Lenggong, Perak. Seventeen adult female Java deer were found dead within a week. Symptoms of dullness, inappetence, anaemia, anorexia, respiratory distress and recumbency were seen prior to death in the infected Java deer. Beside trypanosomiasis, other parasitic infections such as theileriosis, helminthiasis and ectoparasite infestation were also recorded. Post mortem results showed generalized anaemia in most animals with isolated cases of jaundice. There was no significant finding with respect to bacteriological and viral investigations.

Response of four indigenous cattle breeds to natural tsetse and trypanosomosis challenge in the Ghibe valley of Ethiopia.

A comparative study on the response of four indigenous cattle breeds of Ethiopia, namely Abigar, Horro, Sheko and Gurage, to natural challenge of trypanosomosis in the Tolley-Gullele area of the Ghibe valley has been undertaken from August 2000 until August 2004. Fifty female yearlings each of Horro, Sheko and Abigar and 31 of the Gurage were purchased from their natural habitats and introduced in to medium to high tsetse-trypanosomosis challenge area of the Ghibe valley. While the natural habitats of first three breeds are naturally infested with tsetse flies and trypanosomosis, that of the Gurage is known to be very minimal, if any, and hence the Gurage breed was used in this study as the known susceptible breed. During the study animal health, production performance and tsetse fly situation were monitored monthly. The Sheko breed has manifested very significantly (p<0.001) high overall average packed cell volume (PCV) values (25%) compared to that of Abigar (24%), Horro (23%) and Gurage (22%). It also had the lowest mean trypanosome prevalence rate of 9% against 23% of Horro, 26% of Abigar and 27% of Gurage, and the least number of Berenil treatments (1.36) compared to Abigar (4.0), Horro (4.6) and Gurage (6.7). While the Abigar manifested high sensitivity and frequent death to PCV depression, the Horro showed strong resilience to PCV depression and better response to Berenil treatment assistance. At this stage the Sheko breed was also found to be equal to the other breeds in its reproductive performance. These results need to be substantiated with further in-depth investigation including immune response, animal behavior and environmental influences.

Community perceptions of important camel diseases in Lapur Division of Turkana District, Kenya.

This paper presents the results of a study conducted in Lapur Division of Turkana District, Kenya, to estimate the incidence and mortality of camel trypanosomosis using participatory methods. Four livestock camps ('adakars') were conveniently selected for the study. Four informant groups comprising 6 8 key persons were used for the participatory exercises. The camel diseases identified by the pastoralists in their order of importance according to annual incidence were: trypanosomosis (11.4%); mange (10.8%); tick infestation (7.9%); haemorrhagic septicaemia (7.7%); and non-specific diarrhoea (7.6%). Almost half (49.3%) of the camel population suffered from at least one disease over the previous year. The annual incidence and mortality rates of trypanosomosis were estimated at 15%, and 9.9%, in adult camels and 6.9% and 5.2%, in young camels, respectively. There was a seasonal occurrence of trypanosomosis, with most cases reported in the dry season. The prevalence levels of the disease reportedly declined from about 100%, in 1978 to an almost stable state of about 15% in 2002. This study revealed that camel trypanosomosis is still an important disease in Turkana District, exacting a heavy toll in terms of morbidity and mortality. The economic losses due to the disease were likely to have been great owing to the central role the camel plays in this arid district of Kenya.

[Mortality due to infectious and parasitic diseases in the elderly in Brazil]. / A mortalidade por doenças infecciosas e parasitárias na população idosa brasileira.

OBJECTIVE: To describe the mortality due to infectious and parasitic diseases in persons over 65 years of age in all of Brazil and in individual states and to study the association between that mortality due to these causes and specific socioeconomic variables over the period from 1980 to 1995. METHODS: Data were obtained from Brazil's national Mortality Information System. Standardized mortality rates were calculated for tuberculosis, Chagas' disease, and sepsis. The relative contribution of these causes of death to overall mortality was also calculated. The study also analyzed the relationship between mortality rates and gender and the following socioeconomic variables: per capita gross domestic product; number of hospital beds per inhabitant; proportion of the total population living in urban areas; number of benefits provided per capita by the social welfare system; number of deaths reported for every 100 hospitalizations; and life expectancy at birth. A normal multiple linear regression model was used for this analysis. RESULTS: There were no significant changes in the proportion of deaths due to infectious and parasitic diseases in the elderly population during the period studied, regardless of sex. However, for both men and women there was a sizeable decrease in the impact of tuberculosis and Chagas' disease, while that of sepsis appeared to increase. According to the results of the ecological analysis, socioeconomic indicators had little power to explain the differences in mortality patterns seen in the different states of the country. CONCLUSIONS: Our results suggest that policies to prevent and control infectious and parasitic diseases among the elderly in Brazil have stagnated. Given this situation and the progressive increase in the elderly population, mortality due to infectious and parasitic diseases is not likely to decrease in this age group, at least in the near future.

A mortalidade por doenças infecciosas e parasitárias na população idosa brasileira / Mortality due to infectious and parasitic diseases in the elderly in Brazil

OBJETIVO: Traçar o perfil da mortalidade por doenças infecciosas e parasitárias na população de mais de 65 anos no Brasil e nas unidades da federação e investigar sua associação com determinadas variáveis socioeconômicas no período de 1980 a 1995. MÉTODOS: Foram utilizados os dados do Sistema de Informações sobre Mortalidade. Foram calculadas taxas de mortalidade padronizadas para tuberculose, tripanossomíase e septicemia, assim como a participação relativa dessas causas na mortalidade geral. Analisou-se a relação entre as taxas de mortalidade por doenças infecciosas e parasitárias e sexo e as seguintes variáveis socioeconômicas: produto interno bruto per capita; número de leitos hospitalares por habitante; relação entre a população urbana e a total; número de benefícios em manutenção pela previdência social por habitante; coeficiente de letalidade; e esperança de vida ao nascer. Para esta análise foi utilizado o modelo normal de regressão linear múltipla. RESULTADOS: Não houve alteração significativa no percentual de óbitos por doenças infecciosas e parasitárias na população idosa brasileira no período para ambos os sexos. Por outro lado, verificou-se uma importante transição no período, caracterizada pela diminuição da participação da tuberculose pulmonar e da tripanossomíase e pela tendência de aumento na participação da septicemia para ambos os sexos. A análise ecológica mostrou que os indicadores socioeconômicos analisados tiveram baixo poder explicativo para os diferentes padrões de mortalidade nas diferentes regiões do país. CONCLUSÕES: Os presentes resultados sugerem uma estagnação das políticas de prevenção e combate às doenças infecciosas e parasitárias como um todo. Essa observação, juntamente com a progressiva pressão populacional dos idosos, indica que os níveis de mortalidade por doenças infecciosas e parasitárias não deverão diminuir nessa faixa etária, pelo menos em um futuro próximo.

Combination of eflornithine and melarsoprol for melarsoprol-resistant Gambian trypanosomiasis.

OBJECTIVE: To evaluate the efficacy and toxicity of a combination of eflornithine and melarsoprol among relapsing cases of Gambian trypanosomiasis. METHODS: Forty-two late-stage Trypanosoma brucei gambiense trypanosomiasis patients relapsing after initial treatment with melarsoprol were treated with a sequential combination of intravenous eflornithine (100 mg/kg every 6 h for 4 days) followed by three daily injections of melarsoprol (3.6 mg/kg, up to 180 mg). They were then followed-up for 24 months. RESULTS: Two (4.8%) patients died during treatment. Of the 40 surviving patients, two had a treatment failure, 13 and 19 months after having received the combination therapy. By Kaplan-Meier analysis, the 2-year probability of cure was 93.3% (95% confidence interval: 84.3-100%). CONCLUSION: This sequential combination has an efficacy and a toxicity similar to a 7-day course of eflornithine monotherapy, but is easier to administer. Whether such therapeutic success corresponds tosynergism between eflornithine and melarsoprol, or merely means that 4 days of eflornithine monotherapy suffices for such patients, will need to be determined in a comparative trial.

Occurrence of concurrent trypanosomosis, theileriosis, anaplasmosis and helminthosis in Friesian, Zebu and Sahiwal cattle in Uganda.

An epidemiological investigation was conducted on farms in Tororo and Soroti districts of Uganda from January to February 2000 to determine the cause of reported persistent mortality of cattle. Blood and faecal material of 98 cattle comprising of 33 Friesians, 58 Zebu and 7 Sahiwal were examined. Results revealed that seven (7.1 %) cattle had trypanosome infection, mainly due to Trypanosoma vivax and T. brucei, 17 (17.3%) Fasciola infection, 28 (28.6%) gastrointestinal nematode infection, 33 (33.7%) Theileria sp. infection and 13 (13.3%) Anaplasma marginale infection. Mixed infections were detected in 30%, 20.6% and 43 % of the Friesian, Zebu and Sahiwal cattle respectively. Anaemia (PCV < 25) was detected in 24%, 19% and 14% of the Friesian, Zebu and Sahiwal cattle respectively. Persistent mortality of cattle on these farms could have been due to either single or mixed parasitic infections probably exacerbated by malnutrition.

[Biodemes of Trypanosoma cruzi strains isolated from humans from three endemic areas in Minas Gerais State]. / Biodemas de cepas do Trypanosoma cruzi isoladas de humanos de três áreas endêmicas de Minas Gerais.

In order to study the biological behavior of T. cruzi strains and to determine a putative association between their biodeme and the clinical forms of Chagas disease, 14 strains isolated from humans were evaluated. The individuals were from the municipalities of Pains, Iguatama and Berilo (Minas Gerais State). The biological behavior was evaluated in albino swiss mice, weighing 10 to 15 grams, which were infected with 1x10(4) blood tripomastigotes. The infectivity, parasitemia, tripomastigote morphology, virulence and the tissue distribution of the protozoan were analyzed. A behavior similar to biodeme II (São Felipe strain) was observed in 9 strains, while 5 stocks were characterized as belonging to biodeme III. It was not possible to establish a relationship between the biodeme strain and the severity of the disease in the patients.

Trypanosoma evansi control and horse mortality in the Brazilian Pantanal.

The impact of three treatment strategies for Trypanosoma evansi control on horse mortality in the Brazilian Pantanal based on four size categories of cattle ranches is explored. The region's 49,000 horses are indispensable to traditional extensive cattle ranching and T. evansi kills horses. About 13% of these horses would be lost, annually, due to T. evansi if no control were undertaken. One preventive and two curative treatment strategies are financially justifiable in the Pantanal. The best available technology for the treatment of T. evansi from a horse mortality perspective is the preventive strategy, which spares 6,462 horses, annually. The year-round cure spares 5,783 horses, and the seasonal cure saves 5,204 horses on a regional basis relative to no control strategy. Regardless of the strategy adopted, 39% of the costs or benefits fall to the largest ranches, while 18% fall to the smallest ranches.