Detection of pathogenic Leptospira spp. in unconventional pets

Leptospirosis is a disease caused by Leptospira spp. responsible for considerable impacts on the public and animal health. In the past two decades, non-domesticated species of pets (unconventional pets) have become popular. However, the role of these unconventional pets on maintaining diseases still unclear. Therefore, the objective of this study was to survey the presence of Leptospira spp. DNA in unconventional pets. Samples of kidney tissues from 29 animals belonging to the Mammalia class (including Orders Carnivora, Lagomorpha and Rodentia) were analyzed for the presence of the gene lipL32. As a result, DNA of pathogenic Leptospira spp. from specie L. interrogans was detected in four (13,80%) of the analyzed samples: three from Oryctolagus cuniculus and one from Mesocricetus auratus. This study highlights the importance of epidemiological surveillance of leptospirosis, as it identified in species of unconventional pets, that may possibly act as reservoirs of Leptospira spp.

Leptospira borgptersenii and Leptospira interrogans identified in wild mammals in Rio Grande do Sul, Brazil

Leptospira spp. are bacteria responsible for leptospirosis, a zoonotic disease with considerable impacts on the economy, animal health, and public health. This disease has a global distribution and is particularly prevalent in Brazil. Both rural and urban environments are habitats for Leptospira spp., which are primarily transmitted through contact with the urine of infected animals. Consequently, domestic and wild species can harbor these prokaryotes and serve as infection sources for other hosts. In the context of wild animals, there is a dearth of molecular studies elucidating the roles of various animal and bacterial species in the epidemiology of leptospirosis. Therefore, this study aimed to evaluate the presence of Leptospira spp. DNA in different species of free-living and captive wild animals and to assess the phylogenetic relationships of the identified microorganisms in Rio Grande do Sul, Brazil. The samples were evaluated for the presence of the gene lipL32 by polymerase chain reaction (PCR) and sequencing of the amplified fragment after which phylogenetic analyzes were carried out. DNA from Leptospira spp. was extracted from kidney tissue from wild animals (Mammalia class). Pathogenic Leptospira spp. DNA was detected in 9.6% (11/114) of the samples, originating from nine species of wild animals, including the white-eared opossum (Didelphis albiventris), skunk (Conepatus chinga), geoffroy's cat (Leopardus geoffroyi), margay (Leopardus wiedii), pampas fox (Lycalopex gymnocercus), capybara (Hydrochoerus hydrochaeris), common marmoset (Callithrix jacchus), neotropical river otter (Lontra longicaudis), and european hare (Lepus europaeus). Phylogenetic analysis revealed the presence of Leptospira borgpetersenii and Leptospira interrogans in these animals. This research is the first study contributing to the epidemiology of leptospirosis by identifying L. borgpetersenii and L. interrogans in free-living and captive wild animals in Rio Grande do Sul, Brazil, potentially acting as bacterial reservoirs. Additionally, our findings can inform sanitary measures for controlling and preventing the disease, thereby safeguarding public health.

Anti-Leishmania spp. antibody detection in domestic cats from a visceral leishmaniasis transmission area

Feline leishmanial infection is reported worldwide, but the epidemiological role of domestic cats in the leishmaniasis cycle remains unclear, and cats might act as cryptic reservoir hosts in endemic areas with no feline leishmaniosis cases. Considering that, a serological screening for anti-Leishmania spp. antibodies was performed by indirect immunofluorescence antibody test (IFAT) in 389 necropsied cats' serum samples from a new visceral leishmaniasis transmission area with no feline leishmanial infection reported to unveil if the cats are being exposed to the parasite. The overall seroprevalence for Leishmania spp. was 11.05% (43/389). No association was found between sex, neutering status, age group, breed, coat length, feline immunodeficiency virus (FIV) infection, and Leishmania spp. antibody detection. A positive association was found with coat color (cats within the orange spectrum with white [particolor]) (OR = 2.47, CI 95% 1 - 6.13, P = 0.044) and a negative association (OR = 0.38, CI 95% 0.18 - 0.79, P = 0.01) between feline leukemia virus (FeLV) infection and IFAT positivity for Leishmania spp. Therefore, it is concluded that the seroprevalence found was greater than 10%, indicating contact of the protozoan with cats in the region served.

General biosafety measures for laboratory environments, outpatient clinics, medical centers, and veterinary hospitals during the SARS-CoV-2 pandemic

This study aimed to guide professionals working in veterinary laboratories, outpatient clinics, medical centers, and hospitals regarding the biosafety measures that should be adopted during the novel coronavirus (SARS-CoV-2) pandemic. While the population is not yet fully immunized by vaccines, the adoption of biosafety measures is essential to control the spread of circulating strains of the new coronavirus. Thus, the importance of professionals and collaborators following biosafety guidelines in different veterinary work environments is highlighted. The main protocols on biosafety to be adopted include frequent handwashing with water and soap or using 70% alcohol-based hand sanitizers, using personal protective equipment (PPE) (including gloves, lab coat, face mask), avoiding the contact of the hands with mucous membranes (eyes, nose and mouth), not sharing personal objects, keeping environments clean and well ventilated, social distancing of 1.5 m between individuals, and maintaining objects and surfaces regularly clean throughout the work environment. The transformation of work processes, such as various biosafety practices, is necessary within the context of the COVID-19 pandemic and improves the safety of professionals in their work environment and other people and animals, decreasing contamination risks in order to reduce the spread of this viral agent.

Epidemiological aspects of snakebites in the state of Amazonas, Brazil, from 2007 to 2017

This study comprises a retrospective analysis of snakebites in the State of Amazonas, Brazil, from 2007 to 2017. Data were collected from the Notifiable Diseases Information System (NDIS). 17,056 snakebites were recorded in Amazonas between 2007 and 2017. During the study period, the Rio Negro and Tefé micro-regions had the highest accumulated incidence, while small municipalities such as São Gabriel da Cachoeira, Uarini and Alvarães presenting a high incidence rate during the same period. Snakes in the genera Bothrops and Lachesis caused 69.5% and 20.3% snakebites. Snakebites occurred more frequently in the Amazonian winter, between January and April, and most of the snakebite victims (78.6%) were men. The most affected individuals were between 20 and 39 years of age (59.4%). The time elapsed between snakebites and medical assistance varied from one to six hours (51.4%). 7,705 of the snakebite cases, were classified as moderate, 7,328 as mild, and 1,299 as severe. Of the 104 deaths that occurred in the period, Bothrops genus caused the highest mortality (68.3%). The State of Amazonas recorded both high numbers of snakebites in the period 2007-2017 and the time elapsed between snakebite and medical assistance, which may affect the clinical status of patients. KEY WORDS: Bothrops; Lachesis; Amazon; snakes; viperidae

Fungal dermatitis by Scopulariopsis brevicaulisin Guinea pig (Cavia porcellus)

Fungal dermatitis is classified into superficial, cutaneous and subcutaneous mycoses. However, the incidence of fungal dermatitis in small mammals is relatively low. Among rodents guinea pig the most affected specie, however it usually has an asymptomatic pattern. The present text reports an unusual case of fungal dermatitis in Caviaporcelluscaused by Scopulariopsis brevicaulis. The animal was received with complaint of alteration of coat around the neck, as well as report of incorrect feeding management. During the physical examination the presence of a dry and crusty dermatitis, negative on fluorescence test of wood. Samples of blood, skin, scabs and hair were collected for parasitic and mycological analysis. The hematological evaluation showed only a discrete eosinophilia; no ectoparasites were observed, but it was noticed the presence of Scopulariopsis brevicaulis. The animal underwent terbinafine and griseofulvin protocol, with total regression of the lesions after 30 days. S. brevicaulis is an unusual geophilic fungus causing animal mycosis, presenting more pathological reports in human mycoses, thus, representing a zoonotic potential. According to the clinical findings and results obtained from mycology assay, it was diagnosed dermatitis by Scopulariopsis brevicaulis, secondary to nutritional deficiency. The combined use of topical terbinafine with systemic griseofulvin was efficient in the treatment. Finally, it was recommended a dietary correction.

Frequency of leptospirosis in horses in Manaus and metropolitan region in Amazonas State, Brazil

The occurrence of leptospirosis is significantly higher in the tropical climate than in temperate regions, especially in periods with high rainfall levels. In horses, leptospirosis can range from subclinical to asymptomatic but maintains an important role in the transmission of leptospirosis by eliminating the agent in the environment. Regarding horses, the Amazonas herd increased by 30% between 2004 and 2013. Thus, the study aimed to determine the serological prevalence of leptospirosis in horses in Manaus and metropolitan regions, in the State of Amazonas, Brazil as well as to assess the main serogroups involved in the infections of these animals. For this purpose, from August 2018 to July 2019, serum from 198 horses was evaluated through the microscopic agglutination test with a panel of 10 serogroups. As a result, 92 horses (44.46%) were found to be positive for one or more Leptospira serovars, with the highest prevalence of serogroups Icterohaemorrhagiae and Pyrogenes. Therefore, with the increase in the equine herd in the region and, consequently, greater interaction between breeders and animals, the identification of reagents to at least one serovar of Leptospira spp. signals the possible existence of reservoirs of pathogenic strains for other animals and man.

Gastrointestinal protozoa in dairy calves: identification of risk factors for infection

Objective. This study aimed to evaluate the occurrence of gastrointestinal protozoa in dairy calves and to identify potential risk factors for this type of infection. Materials and methods. For this purpose, 243 fecal samples were collected from calves up to 60 days of age in 43 dairy farms located in the West region of Santa Catarina state, Brazil. Samples were examined by centrifugal-flotation technique. Results. As a result, Giardia was present in 26.75% (65/243) of all samples, Eimeria in 21.81% (53/243), and Cryptosporidium in 20.99% (51/243). Additionally, 46.50% (113/243) of the samples were negative for any protozoa, while 39.10% (95/243) and 14.40% (35/208) showed single and mixed infections, respectively. There was a higher association between Cryptosporidium and Giardia (6.99%) in cases of mixed infections. However, the triple protozoa association had the lowest prevalence in mixed infections (2.06%). Epidemiologically, a questionnaire was applied to determine risk factors for these parasitic infections. Based on the statistical model applied, some risk factors for Cryptosporidium infections were identified, highlighting feeding management, period of time that calves stayed with their mothers (cows), and contact with dogs; the risk of contracting Giardia increased according to the milk source, while the floor type bedding, and age were appointed as risks factors for Eimeria. Conclusions. Therefore, it is possible to confirm that Giardia, Cryptosporidium and Eimeria may infect dairy calves, and the knowledge of some risk factors associated to their infection in calves.

Echinococcus granulosus sensu stricto, Echinococcus canadensis (G7), and Echinococcus ortleppi in fertile hydatid cysts isolated from cattle in Southern Brazil

Echinococcosis is a cosmopolitan zoonotic infection that affects humans and animals. The aim of this study was to identify and characterize the fertile hydatid cysts from bovine viscera in order to verify different species and/or genotypes present in Southern Brazil. Firstly, cysts were collected from a slaughterhouse, which received animals from different regions of Rio Grande do Sul State (RS), considered an important area of occurrence of cystic echinococcosis. In total, 2396 cysts were analyzed by microscopy to verify the presence of protoscoleces. Protoscoleces were detected in 291 samples and were classified as fertile hydatid cysts. Total DNA was extracted from protoscoleces and amplified by polymerase chain reaction (PCR). Two hundred and fifty-one samples were identified by PCR and characterized as G5/G6/G7 genotypes, of which 40 belonged to Echinococcus granulosus sensu stricto (G1-G3). PCR was also performed, using G5-specific primers to identify 250 samples as Echinococcus ortleppi (G5). Only one sample was identified as Echinococcus canadensis (G7) by DNA sequencing using primers specific for the coxI gene. Phylogenetic analysis was also performed and identified three distinct groups E1 (G5), E2 (G7), and E3 (G1-G3), which were grouped according to similarity of their sequences. The study highlights the fact that E. granulosus sensu stricto, E. ortleppi, and E. canadensis (G7) were infecting cattle in RS, emphasizing the adaptation of different species of Echinococcus to this intermediate host.

Seroprevalence and risk factors for Neospora caninum in goats in Santa Catarina state, Brazil

Neosporosis is an infectious disease caused by the parasite Neospora caninum. Knowledge regarding neosporosis in goats is still quite limited, especially in the state of Santa Catarina (SC), southern Brazil. Therefore, this study aimed to assess the seroprevalence and risk factors for N. caninum in goats in the western and mountain regions of SC. Blood samples were collected from 654 goats in 57 municipalities. The indirect immunofluorescence test was used for antibody detection against N. caninum. Thirty samples (4.58%) were seropositive, with titers ranging from 1:50 to 1:6400. An epidemiological survey was also conducted in order to identify risk factors for neosporosis in goats. It was found that reproductive problems on the farms, as well as the diet and direct contact with dogs were casual risks for neosporosis. These results indicate that N. caninum infects goats in these regions, which may lead to reproductive problems.

Leptospira Seroprevalence in Capybaras from a Brazilian Urban Area

Background: Leptospirosis remains the most widespread zoonotic disease in the world. As a clinical entity it is strongly associated with regional occupational and environmental exposures.  While the exact global disease burden remains unknown, recent estimates by the leptospirosis Burden Epidemiology Reference Group (LERG) at the World Health Organization have set the number of human cases of severe leptospirosis to over 500,000 per year. This number almost certainly represents an under-representation due to poor surveillance and difficult diagnosis. Leptospira spp. belong to the order Spirochaetales, family Leptospiraceae, composed by 13 pathogenic Leptospira species with more than 260 serovars. Wildlife species are commonly considered to be important epidemiological carriers, mainly because of their frequent reactivity to Leptospira serovars native to their habitat. Capybara (Hydrochaeris hydrochaeris), a known leptospirosis host, is a widespread species in South America. However, reports regarding the importance of this animal in the epidemiology of leptospirosis are rare. Therefore, the objective of this study was to report the results of leptospirosis serological survey of capybaras from a residential park area in southeastern Brazil.Materials, Methods & Results: A total of 172 capybaras were sampled at Itú Municipality, state of São Paulo, southeastern Brazil, from December 2012 to May 2013. Sera samples were examined for Leptospira antibodies by the microscopic agglutination test (MAT), using live antigens grown in liquid medium (EMJH). A complete panel of 7 serogroups (including 10 reference serovars) was used as antigens: serogroup Sejroe (serovars Hardjo and Wolffi), serogroup Grippotyphosa (serovar Grippotyphosa), serogroup Canicola (serovar Canicola), serogroup Icterohaemorrhagiae (serovars Icterohaemorrhagiae and Copenhageni), serogroup Australis (serovars Australis and Bratislava), serogroup Pomona (serovar Pomona), and serogroup Autumnalis (serovar Butembo).   As a results, 46 (26.75%) were serologically positive: 29 (63.05%) for serogroup Sejroe, 7 (15.22%) for serogroup Icterohaemorrhagiae; 9 (19.56%) were seropositive for serogroups Sejroe and Icterohaemorrhagiae; and 1 (2.17%) was positive for serogroups Sejroe and Grippotyphosa.Discussion: L. interrogans sensu stricto is responsible for the most frequent and severe cases of human and animal leptospirosis. Considering the results of our serological survey, it is important to reinforce that in tropical countries, mainly Brazil, India, Thailand, Vietnam, Australia and Barbados, serovars belonging to the Icterohaemorrhagiae serogroup (Icterohaemorrhagiae and Copenhageni) are generally the most prevalent. Therefore, the report of different serogroups in capybaras (as observed in our study) it is an important observation reported. Human leptospirosis is usually due to serovars that are maintained by the animal populations of a region, which spread the bacterium on the environment; thus, it may represent an important additional risk factor for human population. Our study identified a greater serum reactivity to strains that belongs to serogroup Sejroe. In Brazil this serogroup is highly predominant in livestock; thus, our main hypothesis is that some animals were contaminated with Sejroe serovars when they were at their natural habitat and, once in the park, they maintained these serovars through cross transmission.  Therefore, based on our results, it was possible to observe a significant prevalence of serovars belonging to serogroup Icterohaemorrhagiae, and there was also a high prevalence of samples positive to serogroup Sejroe. Thus, our serologic survey showed that capybaras living in an urban area could represent a risk factor for leptospirosis for the human population eventually exposed.

Occurrence of gastrointestinal parasites in goats from the Western Santa Catarina, Brazil

This study aims to investigate the occurrence of gastrointestinal parasites in goats from the Western Santa Catarina, Brazil. Twenty four farms were analyzed in 17 different municipalities. Animals (n=217) from different production purposes (milk and meat) and age were randomly chosen. Fecal samples were collected from the rectum stored in plastic bottles and transported to the laboratory in portable coolers at 10 °C. The technique of centrifugal flotation with saturated sugar solution was carried out in order to investigate the presence of eggs, cysts, and oocysts of gastrointestinal parasites. In 88.9% of the investigated animals, it was observed that the presence of nematode eggs which belongs to the Strongylida order, after cultivation and larvae identification were identified as Haemonchus spp., Trichostrongylus spp., Teladorsagia spp., Cooperia spp., and Oesophagostomum spp. Eggs of Thysanosoma, Trichuris, Moniezia, and Neoascaris genus were also observed. Additionally, the presence of oocysts of Eimeria spp. and Cryptosporidium spp. as well as cysts of Giardia spp., and Entamoeba spp. were verified. In all the farms evaluated, the animals showed a single or mixed infection, with the highest occurrence of helminths belonging to the Haemonchus and Trichostrongylus genus, as well as the protozoan Eimeria.

Echinococcus granulosus sensu lato and Taenia hydatigena in pig in southern Brazil

This study aimed to identify the parasitical etiologic agents of visceral cysts in pigs from the central/northern region of Rio Grande do Sul State, Brazil. Fifty-eight cysts were found in livers during veterinary inspection of swine slaughtered from January 2008 to 2012. Collected samples were submitted to macroscopic and molecular analyzes. Polymerase chain reaction (PCR), DNA sequencing and BLAST alignment of sequences was used to molecular characterization of the samples. By PCR 10.3% (6/58) of tested samples were positive for Echinococcus granulosus sensu lato and 56.9% (33/58) for Cysticercus tenuicollis. In this study, it was verified the occurrence of larval forms of E. granulosus sensu lato and Taenia hydatigena in pig herds from the central/northern region of Rio Grande do Sul State. The presence of both parasites is relevant due to the economic losses for the meat industry. Additionally, E. granulosus sensulato has zoonotic importance and may be infecting pig herds in southern Brazil.

Serum levels of nitric oxide and protein oxidation in goats seropositive for Toxoplasma gondii and Neospora caninum

The aim of this study was to assess and analyze the levels of nitric oxide (NO) and advanced oxidation protein products (AOPP) in serum of goats naturally infected by Toxoplasma gondii, Neospora caninum, or concomitantly infected by these two parasites. Thus, it was measured NOx and AOPP levels in twenty (n=20) sera samples of goats seronegative for T. gondii and N. caninum [negative control group (A)]; while the positive groups were composed by sera of infected animals, twelve (n=12) seropositive for N. caninum [group B]; eighteen (n=18) positive for T. gondii [group C]; and thirteen (n=13) seropositive for N. caninum and T. gondii [group D]. As results, it was observed that animals seropositive for N. caninum and T. gondii (Groups B to D) showed higher serum levels of NOx (P<0.001; F=9.5), when compared with seronegative animals. Additionally, it was observed a positive correlation between NOx levels and antibodies titrations for N. caninum (P<0.01; r=0.68) and T. gondii (P<0.05; r=0.56). AOPP levels were increase in groups C and D (P>0.05). Interestingly, group B did not show increase in AOPP, what led us to hypothesize that the major protein damage is linked to T. gondii infection. Therefore, our results showed an increased in NOx levels, which was probably related to the immune response, since it is an important inflammatory mediator; and AOPP were increased in groups where there was seropositivity for T. gondii, but not for the group composed only by animals seropositive for N. caninum, allowing us to suggest higher protein damage in toxoplasmosis.

Influence of Toxoplasma gondii acute infection on cholinesterase activities of Wistar rats

Several studies have shown the mechanisms and importance of immune responses against Toxoplasma gondii infection and the notable role of cholinesterases in inflammatory reactions. However, the association between those factors has not yet been investigated. Therefore, the aim of this study was to evaluate the acetylcholinesterase (AChE) activity in blood and lymphocytes and the activity of butyrylcholinesterase (BChE) in serum of rats experimentally infected with T. gondii during the acute phase of infection. For that, an in vivo study was performed with evaluations of AChE and BChE activities on days 5 and 10 post-infection (PI). The activity of AChE in blood was increased on day 5 PI, while in lymphocytes its activity was enhanced on days 5 and 10 PI (P<0.05). No significant difference was observed between groups regarding to the activity of BChE in serum. A positive (P<0.01) correlation was observed between AChE activity and number of lymphocytes. The role of AChE as an inflammatory marker is well known in different pathologies; thus, our results lead to the hypothesis that AChE has an important role in modulation of early immune responses against T. gondii infection.

Role of acute phase proteins in the immune response of rabbits infected with Trypanosoma evansi

The aim of this study was to characterize the response of acute phase proteins (APP) in rabbits experimentally infected with Trypanosoma evansi (T. evansi), and to relate the findings with serum immunoglobulins levels, in order to verify the relation between APP and the immune response of rabbits. A total of 12 animals were used in this experiment and divided into 2 groups, control and infected, of six rabbits each. The experimental period was 118 days, and blood was collected on days 0, 5, 20, 35, 65, 95 and 118 post-infection (PI). The infection with T. evansi stimulated APP and immunoglobulins production, once the infected animals showed an increase in C-reactive protein, haptoglobin, alpha 2-macroglobulin and IgM levels. The elevation in IgM levels observed in this study, when related to the increase in C-reactive protein and haptoglobin levels, suggests the involvement of these proteins in host defense against flagellated protozoa, with possible participation in the control of the parasitemia in rabbits infected with T. evansi.

Lice outbreak in buffaloes: evidence of Anaplasma marginale transmission by sucking lice Haematopinus tuberculatus

Lice infestations are commonly seen in buffaloes, causing damage directly to the animal, i.e., itching, skin lesions, and anemia. In addition, these insects can also be vectors for infectious diseases. The present study describes an outbreak of lice in buffaloes as well as evidence for Haematopinus tuberculatus acting as a vector of anaplasmosis. Lice and blood were collected from 4 young buffaloes (2- to 4-mo-old) and a molecular analysis for the presence of Anaplasma marginale was conducted. DNA of A. marginale was detected in the blood of all 4 animals. Twelve lice were collected and separated in 4 groups, with 3 insects each, to comprise a pool of samples. After DNA extraction and molecular analysis, a positive PCR for A. marginale was found in all pooled samples. These results identify sucking lice as potential vectors of anaplasmosis. However, additional studies are necessary to fully evaluate the vector potential of H. tuberculatus for A. maginale transmission.

Trypanocidal activity of human plasma on Trypanosoma evansi in mice

This study aimed to test an alternative protocol with human plasma to control Trypanosoma evansi infection in mice. Plasma from an apparently 27-year-old healthy male, blood type A+, was used in the study. A concentration of 100 mg.dL(-1) apolipoprotein L1 (APOL1) was detected in the plasma. Forty mice were divided into four groups with 10 animals each. Group A comprised uninfected animals. Mice from groups B, C and D were inoculated with a T. evansi isolate. Group B was used as a positive control. At three days post-infection (DPI), the mice were administered intraperitoneally with human plasma. A single dose of 0.2 mL plasma was given to those in group C. The mice from group D were administered five doses of 0.2 mL plasma with a 24 hours interval between the doses. Group B showed high increasing parasitemia that led to their death within 5 DPI. Both treatments eliminated parasites from the blood and increased the longevity of animals. An efficacy of 50 (group C) and 80% (group D) of human plasma trypanocidal activity was found using PCR. This therapeutic success was likely achieved in the group D due to their higher levels of APOL1 compared with group C.

Activity of cholinesterases and adenosine deaminase in blood and serum of rats experimentally infected with Trypanosoma cruzi

This study aimed to evaluate the activity of cholinesterases and adenosine deaminase (ADA) in blood and serum of rats infected with Trypanosoma cruzi. Twelve adult rats were used in the experiment divided into two uniform groups. Rodents from group A (control group) were non-infected and animals from group B served as infected, receiving intraperitoneally 3·3×10(7) trypomastigotes/each. Blood collection was performed at days 60 and 120 post-infection (PI) in order to evaluate the hemogram, blood activity of acetylcholinesterase, and serum butyrylcholinesterase and ADA activities. Hematological parameters did not differ between groups. A significant increase (P<0·05) of acetylcholinesterase activity was observed in blood while butyrylcholinesterase had a significant reduction (P<0·01) in serum of infected rats at days 60 and 120 PI. ADA activity in serum showed an inhibition in infected animals when compared to non-infected at day 120 PI. Based on these results, it is possible to conclude that the activity of cholinesterases and ADA were changed in animals infected with T. cruzi. The possible causes of these alterations will be discussed in this paper.