Acute Trypanosomiasis Research Articles

Acute trypanosomiasis in a dog from Brazil: a case report study

Acute trypanosomiasis in a dog from Brazil: a case report study

Parasitological and clinical-pathological findings in twelve outbreaks of acute trypanosomiasis in dairy cattle in Rio de Janeiro state, Brazil

In Brazil, infection in cattle was first reported in the state of Pará, in 1944, and the presence of the parasite has already been recorded in several states. The purpose of this study was to report the clinical-pathological aspects of a natural infection by T. vivax in dairy cattle in the state of Rio de Janeiro. Twelve outbreaks of the infection were diagnosed in 11 municipalities from April 2016 to October 2018. All properties had acquired cattle from states where the disease had already been recorded and it was found that needles for oxytocin administration had been shared. These outbreaks were studied by visiting the properties to perform anamnesis, clinical exams and collection of material for laboratory diagnosis. Laboratory diagnosis was performed through parasitological, molecular and histopathological techniques. Animals with confirmed diagnosis for T. vivax showed anemia, lack of appetite, decreased milk production, weight loss, weakness, abortion, diarrhea and neurological signs. The main histological lesions found were meningoencephalitis and lymphohistiocytic myocarditis. In the central nervous system, the lesions were more severe in the brain compared to the spinal cord, being progressively more severe in the rostro-dorsal direction. Also, they were more accentuated in the white matter compared to the gray matter. Due to nonspecific clinical signs, laboratory tests were key for diagnosis. Trypanosomiasis in cattle herds in the state of Rio de Janeiro, Brazil, is of great concern because of its potential to cause economic losses.

Targeting the parasite's DNA with methyltriazenyl purine analogs is a safe, selective, and efficacious antitrypanosomal strategy.

The human and veterinary disease complex known as African trypanosomiasis continues to inflict significant global morbidity, mortality, and economic hardship. Drug resistance and toxic side effects of old drugs call for novel and unorthodox strategies for new and safe treatment options. We designed methyltriazenyl purine prodrugs to be rapidly and selectively internalized by the parasite, after which they disintegrate into a nontoxic and naturally occurring purine nucleobase, a simple triazene-stabilizing group, and the active toxin: a methyldiazonium cation capable of damaging DNA by alkylation. We identified 2-(3-acetyl-3-methyltriazen-1-yl)-6-hydroxypurine (compound 1) as a new lead compound, which showed submicromolar potency against Trypanosoma brucei, with a selectivity index of >500, and it demonstrated a curative effect in animal models of acute trypanosomiasis. We investigated the mechanism of action of this lead compound and showed that this molecule has significantly higher affinity for parasites over mammalian nucleobase transporters, and it does not show cross-resistance with current first-line drugs. Once selectively accumulated inside the parasite, the prodrug releases a DNA-damaging methyldiazonium cation. We propose that ensuing futile cycles of attempted mismatch repair then lead to G2/M phase arrest and eventually cell death, as evidenced by the reduced efficacy of this purine analog against a mismatch repair-deficient (MSH2−/−) trypanosome cell line. The observed absence of genotoxicity, hepatotoxicity, and cytotoxicity against mammalian cells revitalizes the idea of pursuing parasite-selective DNA alkylators as a safe chemotherapeutic option for the treatment of human and animal trypanosomiasis.

2,4-Diaminopyrimidines as Potent Inhibitors of Trypanosoma brucei and Identification of Molecular Targets by a Chemical Proteomics Approach

BackgroundThere is an urgent need to develop new, safe and effective treatments for human African trypanosomiasis (HAT) because current drugs have extremely poor safety profiles and are difficult to administer. Here we report the discovery of 2,4-diaminopyrimidines, exemplified by 4-[4-amino-5-(2-methoxy-benzoyl)-pyrimidin-2-ylamino]-piperidine-1-carboxylic acid phenylamide (SCYX-5070), as potent inhibitors of Trypanosoma brucei and the related trypanosomatid protozoans Leishmania spp.Methodology/Principal FindingsIn this work we show that loss of T. brucei viability following SCYX-5070 exposure was dependent on compound concentration and incubation time. Pulse incubation of T. brucei with SCYX-5070 demonstrates that a short period of exposure (10–12 hrs) is required to produce irreversible effects on survival or commit the parasites to death. SCYX-5070 cured an acute trypanosomiasis infection in mice without exhibiting signs of compound related acute or chronic toxicity. To identify the molecular target(s) responsible for the mechanism of action of 2,4-diaminopyrimidines against trypanosomatid protozoa, a representative analogue was immobilized on a solid matrix (sepharose) and used to isolate target proteins from parasite extracts. Mitogen-activated protein kinases (MAPKs) and cdc2-related kinases (CRKs) were identified as the major proteins specifically bound to the immobilized compound, suggesting their participation in the pharmacological effects of 2,4-diaminopyrimidines against trypanosomatid protozoan parasites.Conclusions/SignificanceResults show that 2,4-diaminopyrimidines have a good in vitro and in vivo pharmacological profile against trypanosomatid protozoans and that MAPKs and CRKs are potential molecular targets of these compounds. The 2,4-diminipyrimidines may serve as suitable leads for the development of novel treatments for HAT.

Transmission ofTrypanosoma cruziby Heart Transplantation

Trypanosoma cruzi infection (i.e., Chagas disease) is an unusual complication that can occur after solid-organ transplantation and that can result in severe illness or death. In 2006, there were 2 heart transplant recipients in Los Angeles, California, reported to have acute trypanosomiasis during the same month. We conducted an investigation to determine the source of these infections. We reviewed the medical, organ procurement, and donor transfusion and transplantation records of these 2 heart transplant recipients. The 2 heart transplant recipients were interviewed regarding any kind of natural exposure and were screened for parasites by obtaining blood and other tissue samples for buffy coat, culture, and polymerase chain reaction. Serum samples from the heart transplant recipients, organ donors, and blood donors were tested for T. cruzi antibodies by use of immunofluorescence assay and radioimmunoprecipitation assay. Tissue samples from the organ donors were examined by use of polymerase chain reaction and immunohistochemical staining. Other recipients of organs from the same donors were monitored for T. cruzi infection by use of polymerase chain reaction and immunofluorescence assay. Both heart transplant recipients had no apparent risk factors for preexisting T. cruzi infection. Both were seronegative but tested positive for the parasite, indicating recent infection. Both recipients died despite medical treatment. The organ donors tested positive for T. cruzi antibodies by use of radioimmunoprecipitation assay; the blood donors were seronegative. Six other patients had received a liver or kidney from these organ donors. None showed evidence of T. cruzi infection. To our knowledge, this is the first report of T. cruzi transmission associated with heart transplantation. Clinicians and public health authorities should be aware that manifestations of Chagas disease can occur after transplantation, requiring rapid evaluation, diagnosis, and treatment.

Trypanocidal activity of arsonoliposomes: Effect of vesicle lipid composition

Sonicated arsonoliposomes were prepared using an arsonolipid with palmitic acid acyl chain (C16), mixed with phosphatidylcholine (PC-based) or 1,2-distearoyl- sn-glycero-3-phosphocholine (DSPC-based), and cholesterol (Chol) with a molar ratio C16 /PC or DSPC/ Chol 8:12:10. PEG-lipid (1,2-distearoyl- sn-glycero-3-phosphoethanolamine conjugated to polyethylenoglycol 2000) containing vesicles (pegylated-arsonoliposomes) were also prepared. The in vitro and in vivo trypanocidal activity of the various types of arsonoliposomes was evaluated. Although PC-based arsonoliposomes exhibited in vivo activity on an acute trypanosomiasis animal model, no evidence of activity was demonstrated for DSPC-based or pegylated-arsonoliposomes on a chronic model. Despite the fact that DSPC-based and pegylated-arsonoliposomes have better bioavailability compared to PC-based ones, their in vitro activity is lower than that of PC-based arsonoliposomes, indicating the importance of arsonoliposome lipid composition on their trypanocidal activity and suggesting that further arsonoliposome structure design is required to overcome these disadvantages.

Trypanosomes on the Web

Two visitors to the Serengeti National Park in Tanzania were infected with Trypanosoma brucei rhodesiense. As reported to the ProMED-mail list, an American tourist, there for only 2 days in May, in Nepal a week later was found to have acute trypanosomiasis; a British man there for 3 days also acquired the parasite. Both had a chancre at the site of infection, both had noticed tsetse bites. These cases, unusual after such brief exposure, were presented at the recent ASTMH meeting. David Freedman (GeoSentinel Network, University of Alabama at Birmingham, USA) commented that its database covering 26 global sites since 1997 contains no other cases of East African trypanosomiasis in travellers. [A.Sinha et al., African trypanosomiasis in two travelers from the United States.Clin. Infect. Dis. 29, 840–844, 1999 includes reviews of 29 other published cases.]

Hypothalamic-pituitary-adrenal axis responsiveness to insulin-induced hypoglycaemia is modified by trypanosome infection in Boran ( Bos indicus) cattle

Ten Boran ( Bos indicus) cattle were used to study the stress responsiveness of the hypothalamic-pituitary-adrenal ( HPA) axis during trypanosome infection. Five cattle were infected with Trypanosoma congolense IL 1180 by tsetse challenge and five cattle served as controls. All infected animals developed acute trypanosomiasis. Insulin-induced hypoglycaemia (50 per cent of pre-insulin glucose concentration) was used as a stress factor. Acute hypoglycaemia was observed in three infected and three control animals after insulin challenge. Two animals from each group either did not respond or responded slowly. Hypoglycaemia in infected animals completely failed to induce an HPA axis response, while in control animals an HPA axis response was indicated by a significant increase in plasma adrenocorticotrophic hormone ( ACTH) and cortisol concentrations (P<0·01). The results show that trypanosomiasis in Boran cattle can cause a decrease in the stress responsiveness of the HPA axis as indicated by a blunted ACTH/cortisol response to insulin-induced hypoglycaemia.

Acute Trypanosoma vivax infection of Ethiopian cattle in the apparent absence of tsetse.

Investigations of acute trypanosomiasis in a group of 1,200 cattle provided strong evidence for mechanical transmission by haematophagous flies other than tsetse. Although recently introduced cattle may have had previous contact with tsetse flies the incident occurred in an area remote from their known range. Mortality exceeded 6% before the outbreak was controlled by chemotherapy. Mechanically transmitted Trypanosoma vivax infection may be of widespread occurrence in eastern Ethiopia.

Experimental chronic Trypanosoma brucei rhodesiense infection in Microtus montanus.

Adult Microtus montanus were inoculated with a recently isolated strain of Trypanosoma brucei rhodesiense of human origin. The animals developed subacute to chronic infection and low-grade parasitemia. Histopathological examination of the heart revealed a severe pancarditis resulting in pronounced weight loss, and survival times of 5-8 weeks, preventing development of meningoencephalitis. In the brain a moderate meningitis was found, usually associated with moderate numbers of parasites in the choroid plexus and leptomeninges; however, trypanosomes were also found without tissue inflammation. Meningoencephalitis was found after 7 weeks, with parasites in the cerebral parenchyma. Chronic inflammation was present in lungs and kidney, often associated with trypanosomes; in one animal glomerulonephritis was found. Spleen and lymph glands showed a variable degree of lymphoid hyperplasia but no extravascular parasites. In the liver of all animals plasmolymphoid infiltrates were observed in the periportal connective tissue; no extravascular parasites were observed. A variable degree of lymphoplasmohistiocytic infiltrate in the connective tissue and occasional rare trypanosomes were seen in mesenterium, pancreas, epididymis, striated muscle, and skin. Experimental infection in M. montanus appears to be a suitable model for study of the acute trypanosomiasis of T. b. rhodesiense, but not for chronic African sleeping sickness with cerebral involvement.

An accidental laboratory infection with trypanosomes of a defined stock II. Studies on the serological response of the patient and the identity of the infecting organism

Summary We describe the serological investigation of a student who developed acute trypanosomiasis whilst working with the ETat variable antigen types of a stock of Trypanosoma brucei ssp which was thought to be non-infective for man. The patient exhibited the extreme elevation of IgM typical in this disease but no serological evidence was obtained to show that this represented anything but a specific response to antigens of the infecting organism. The IgM deteriorated rapidly during storage. Immunoglobulin E was also considerably increased above normal. Serological evidence was obtained that the infection was initiated by variable antigen type ETat 10, which organism appears to be the only one from the ETat serodeme that, when grown in rodents, is infective for man.

Serum Immunoglobulin Levels in Sheep During the Course of Naturally Acquired and Experimentally Induced Trypanosomiasis

SUMMARY The serum levels of immunoglobulin M (IgM) and G (IgG) were determined in sheep during the course of natural infections due to T. congolense alone and mixed infections of T. congolense and T. vivax and in experimentally induced infections of one isolate of T. congolense and four isolates of T. brucei group trypanosomes. A significant rise in IgM levels occurred in all the sheep within two weeks. IgG levels increased in all sheep except those dying from acute trypanosomiasis due to experimental infection with T. congolense. The results of these investigations are contrasted with those of other authors.

The pathology and pathogenesis of Trypanosoma vivax infection in the goat

Acute and chronic forms of disease can be distinguished in Trypanosoma vivax infection in the goat. The main difference between the acute and chronic form seems to be the presence of microthrombi in the acute stage of infection; these consist of platelets, trypanosomes, monocytoid cells and some fibrin. This thrombus formation seems directly related to the high parasitaemia in acute trypanosomiasis and may result in ischaemia which could also explain the haemorrhages, the oedema of the lungs and other tissues, and the necrotic changes found in several organs. The anaemia, associated with erythrophagocytosis, haemosiderosis, extramedullary haemopoiesis and hyperactivity of the bone marrow, seemed to be of haemolytic origin. The factors leading to emaciation seemed to be degenerative atrophy of muscular tissue and loss of protein in the urine caused by a possible immune complex glomerulonephritis.

Chemotherapy of African sleeping sickness: III. Chemotherapy of experimental Trypanosoma gambiense and Trypanosoma rhodesiense infections in mice with captostibone

1. (1) Acute, always fata, Trypanosoma gambiense and Trypanosoma rhodesiense infections in mice ( Mus musculus) were cured with adequate dosages of captostibone [sodium 2-(carboxy-methylmercapto) benzene stibonate]. 2. (2) Administration of 150 to 200 mg./kg. of captostibone sodium daily for 4 days intraperitoneally produced from 80 to 100 per cent. curative effects in mice infected with T. gambiense or T. rhodesiense; with dosages ranging from 75 to 125 mg./kg. daily for 4 days, percentages of cures were less. 3. (3) All mice that survived and remained free of trypanosomes were discarded as cured 60 to 212 days following cessation of therapy. 4. (4) One hundred and fifty-five untreated control mice, 70 infected with T. gambiense and 85 infected with T. rhodesiense, all invariably died of acute trypanosomiasis in from 3 to 5 days.

Chemotherapy of experimental Chagas' disease with thirty antibiotics.

SummaryThe following antibiotics were tested against Trypanosoma cruzi both in vitro and in vivo, 23 for the first time: 1. acti-dione; 2. antibiotic S; 3. aureomycin hydrochloride; 4. bacillin culture filtrate; 5. bacitracin—topical; 6. borrelidin sodium; 7. Bristol A6786-52; 8. chloramphenicol (chloromycetin); 9. circulin (antibiotic Q-19); 10. dihydrostreptomycin sulfate; 11. endomycin; 12. fradicin; 13. fumagillin; 14. gliotoxin; 15. gramicidin; 16. neomycin sulfate; 17. penicillin G sodium; 18. penicillin O potassium (allymercaptomethyl); 19. 1,2-diphenyl-2-methylamine ethanol penicillin; 20. pleocidin; 21. polymyxin B sulfate; 22. rimocidin; 23. streptomycin sulfate; 24. subtilin; 25. terramycin hydrochloride; 26. thiolutin; 27. tyrocidine hydrochloride; 28. tyrothricin; 29. viomycin sulfate; 30. viridin.In vitro tests were performed by a newly developed method with the 30 antibiotics against two strains of Tr. cruzi (Pack-Brazil-46 and WBHT). Out of the 30 antibiotics, 18 showed immobilizing or trypanocidal effects at the end of 5, 10, 15, and 60 minutes or at the end of 24 hours. The trypanostatic or trypanocidal effects ranged from dilutions of 1:10 to as high as dilutions 1:400,000, depending upon the antibiotics and time of contact periods. The remaining 12 antibiotics (Nos. 4, 5, 6, 7, 10, 13, 15, 16, 18, 19, 23, 29), used in highest concentrations practical, were innocuous to Tr. cruzi in vitro at the end of 24 hours' exposure period.In vivo tests, in spite of the above findings, were all essentially negative. None of the above 30 antibiotics, when administered intraperitoneally in maximum tolerated doses into mice infected with the virulent WBHT strain of Tr. cruzi, produced an absolute cure. All of the experimental animals, with the exception of a few which developed chronic infections, died of acute trypanosomiasis within two weeks. A few instances of suppressive action were obtained with the following antibiotics: endomycin, gramicidin, rimocidin, antibiotic S, thiolutin, tyrocidine hydrochloride, tyrothricin, and viridin. Although there were definite reductions in the number of trypanosomes present in the blood of these mice as compared with the number in the untreated mice, many died earlier than did the controls because of the toxicity of the drugs. The most marked suppression was produced by antibiotic S. However, no curative effects were obtained.

The Cattle Reservoir for Equine Trypanosomiasis in Panama

Summary 1. Native cattle of the Republic of Panama can act as an important reservoir for T. hippicum, the cause of equine trypanosomiasis. Our survey methods indicate that the cattle carrier index will range from 2 to 6 per cent where the horse disease is present. 2. Length of the carrier state. Thick blood films will reveal a scant number of trypanosomes from the time of inoculation for about two weeks. The six calves ranged from eleven to eighteen days. One film from calf 2 was positive on a day about six months after its inoculation but there were none positive between the twelfth day and that remote period. Guinea pig tests show that the six calves failed to infect anywhere from two to six months after they acquired the infection. The complement fixation test applied to four of the calves showed a positive response at the end of six months in three and at the end of nine months in one. The calves were killed and we can not state with certainty when this response might have failed. We know it failed to respond in 16 horses cured of the disease in 1930 to 1931 and tested in August, 1934. 3. The complement fixation test should be of practical use in surveying a herd of cattle for carriers. 4. Physical condition of the calves. The calves grew in a normal manner and were fatter than cattle of a similar age left on the range. 5. The 5 strains of T. hippicum recovered from range cattle were injected into healthy horses. An acute trypanosomiasis developed similar in all respects to the strains formerly recovered from horses. 6. Three vampire bats (Desmodus rotundus murinus) were fed on cattle carriers. One acquired the disease and transferred it to a guinea pig. Two failed to acquire the disease. It is quite evident that the peripheral blood of an animal must contain a fair number of the trypanosomes at the time the bat feeds on it.