Ana Paula Peconick

Congenital Neosporosis in Goats from the State of Minas Gerais, Brazil

Congenital Neospora caninum infection was diagnosed in two Saanen goat kids from two distinct herds with a history of abortion and weak newborn goat kids in the Southern region of the State of Minas Gerais, Brazil. The first kid was weak at birth, had difficulty to rise and was unable to nurse. Gross lesions of porencephaly and hydrocephalus ex vacuo were seen. Multifocal necrosis, gliosis and non-supurative encephalitis were observed in the brain. Several parasitic cysts with a thick wall that reacted strongly only with polyclonal antiserum to Neospora caninum were seen in the cerebral cortex, brain stem and cerebellum. The second kid was born from a Neospora caninum seropositive mother that aborted in the last pregnancy. It was born without clinical signs. The diagnosis of neosporosis was based on antibody titer of 1:800 to N. caninum by indirect fluorescence antibody test obtained from blood collected before the goat kid ingested the colostrum and Neospora caninum DNA was detected by polymerase chain reaction and sequenced from placenta. This is the first report of neosporosis in goats in the southeast region of Brazil.

Antibody kinetics in goats and conceptuses naturally infected with Neospora caninum

Neospora caninum is a protozoan which can cause abortions in caprines. However, information regarding the humoral immune response and the occurrence of reproductive disorders is scarce. This is the first study in which the kinetics of antibodies is studied in pregnant goats naturally infected by N. caninum, as well as their respective conceptuses. The subclasses of IgG (IgG1 and IgG2) were also evaluated in pregnant goats. Reproductive problems related to neosporosis (abortion and stillbirth) occurred in 15.38% of the goats. There was a statistically significant association between the increased titres of maternal IgG in the second half of the gestational period with the occurrence of endogenous transplacental transmission. The rate of congenital transmission was 77%. During the gestational period of the seropositive goats, there was mainly a predominance of the subclass IgG2, although mixed patterns of IgG2-IgG1 and the IgG1 pattern were also observed. These results indicate that N. caninum is responsible for the occurrence of important alterations in the humoral immune response of naturally infected goats, and is also a potential causative agent for reproductive disorders in goats. The high proportion of infected conceptuses reinforces the suggestion that congenital infection is one of the main routes of parasite transmission in goats.

Risk factors associated with seroprevalence of Neospora caninum in dogs from urban and rural areas of milk and coffee production in Minas Gerais state, Brazil

This study was conducted to determine the seroprevalence of anti-Neospora caninum antibodies and to investigate the risk factors related to seroprevalence in dogs from urban and rural areas with distinct economic activities (milk and coffee production) in Minas Gerais state, Brazil. For this purpose, blood samples from 703 dogs were collected and questionnaires addressing epidemiological aspects were completed by dog-owners. The sera were analysed for anti-N. caninum antibodies by indirect fluorescent antibody tests (IFAT ≥ 1:50). Association between epidemiological aspects and seropositivity in dogs was evaluated with multivariate logistic regression models. A total of 80 (11·4%) dogs tested positive for N. caninum. In the multivariate logistic regression models, dogs aged >4 years, dogs used as guard dogs, dogs that spontaneously hunt, and history of bovine abortion were found to be greater risk factors for canine N. caninum infection. When we considered only dogs from rural areas, an association with seroprevalence was seen for milk farms, dogs not fed with commercial food, dogs that hunt, and dogs used as guard dogs.

Histological and immunohistochemical characterization of the inflammatory and glial cells in the central nervous system of goat fetuses and adult male goats naturally infected with Neospora caninum

BackgroundNeospora caninum is an apicomplexan protozoan that is considered one of the main agents responsible for abortion in ruminants. The lesions found in the central nervous system (CNS) of aborted fetuses show multifocal necrosis, gliosis, and perivascular cuffs of mononuclear cells, but the inflammatory and glial cells have not been immunophenotypically characterized. The lesions in the CNS of infected adult animals have rarely been described. Therefore, in this study, we characterized the lesions, the immunophenotypes of the inflammatory and glial cells and the expression of MHC-II and PCNA in the CNS of goats infected with N. caninum. The CNS of eight aborted fetuses and six adult male goats naturally infected with N. caninum were analyzed with lectin histochemistry (RCA1) and immunohistochemistry (with anti-CD3, −CD79α, −GFAP, −MHC-II, and -PCNA antibodies). All animals were the offspring of dams naturally infected with N. caninum.ResultsThe microscopic lesions in the CNS of the aborted fetuses consisted of perivascular cuffs composed mainly of macrophages (RCA1+), rare T lymphocytes (CD3+), and rare B lymphocytes (CD79α+). Multifocal necrosis surrounded by astrocytes (GFAP+), gliosis composed predominantly of monocytic-lineage cells (macrophages and microglia, RCA1+), and the cysts of N. caninum, related (or not) to the lesions were present. Similar lesions were found in four of the six male goats, and multinucleate giant cells related to focal gliosis were also found in three adult goats. Anti-GFAP immunostaining showed astrocytes characterizing areas of glial scarring. Cysts of N. caninum were found in three adult male goats. The presence of N. caninum was evaluated with histopathology, immunohistochemistry, and PCR. Immunohistochemistry demonstrated anti-PCNA labeling of macrophages and microglia in the perivascular cuffs and the expression of MHC-II by microglia and endothelial cells in the CNS of the aborted fetuses and adult male goats.ConclusionsMacrophages and microglia were the predominant inflammatory cells in the CNS of aborted fetuses and healthy adult male goats infected with N. caninum. Activated astrocytes were mainly associated with inflamed areas, suggesting that astrocytes were involved in the resolution of the lesions.

Abortos por Neosporacaninum em bovinos do sul de Minas Gerais

The present study evaluates the participation of Neospora caninum in bovine abortions from farms in the southern region of Minas Gerais state, Brazil, through histopathological, immunohistochemical (IHQ) analysis and DNA detection by polymerase chain reaction (PCR). The material used in this study was obtained through retrospective study of bovine abortion cases received by the Setor de Patologia Veterinaria da Universidade Federal de Lavras and by necropsies performed in fetuses from 2011 to 2013. From 60 fetuses studied, 30 (50%) had microscopic lesions; 19 (63%) of them had histologic lesions compatible with N. caninum abortion, characterized by multifocal non-suppurative encephalitis, necrosis and gliosis in the central nervous system and multifocal nonsuppurative myocarditis and myositis. From the 19 fetuses with protozoa lesions in 14 the final diagnosis was performed; five were confirmated only by IHQ staining and five were positive only by PCR. Four fetuses were positive in IHC and in PCR. In five fetuses from the retrospective study lesions compatible with N. caninum were seen, but the presence of the protozoan was not confirmed by IHQ labeling. The findings demonstrate that N. caninum is an important agent associated with abortion in cattle from Minas Gerais. Therefore, beyond the microscopic lesions association between IHC and PCR was essential to confirm the diagnosis.

Parasitic Infections and Inflammatory Diseases

The mammalian immune system is continuously exposed to infectious microorganisms as well as innocuous substances in the environment. Depending on the genetic makeup, the innate and adaptive immune responses develop and determine the frequency and the course of infectious diseases. The immune response to an infection is initiated by molecular recognition of damage-associated patterns (DAMPs) by receptors of the innate immunity, that, most of the time, occurs as an inflammatory reaction (Turvey & Broide, 2010). The inflammation associated to parasite organisms is a complex reaction of the vascular tissues against infection, exposition to toxins or cellular injury involving extravascular accumulation of plasmatic proteins and leukocytes, as well as production of cytokines from the injured tissue. It is an essential component of multifactorial pathogenesis involved in different diseases (Scrivo et al., 2011). The acute inflammation is a common result of innate immune response; however local immune adaptative factors can also promote inflammation (Lukic et al., 2009). The morphologic transformations and functional characteristics of immunological responses and consequently, of the inflammatory processes intend to destroy, to dilute or to isolate the harmful agent. Virtually, all the acute or chronic diseases are lead or modulated by the inflammation. Although the inflammation serves to a protective function in the control of parasitic infections and promotion of tecidual repair, this can also cause injury and illness itself. Schistosomiasis is an exemple of parasitary disease caused predominantly by the host immune response to schistosome eggs (ova) and the granulomatous reaction they evoke (Burke et al., 2009). In some cases, the inflammation can even persist after the removal of the infectious agent, contributing to the chronic inflammation (Vodovotz et al., 2009). Amongst the various infectious agents, helminth parasites are regarded as master manipulators of the host immune system, often inducing a long-lasting asymptomatic form of infection. Parasitic worms can establish and reproduce in mammalian hosts, switching off the inflammatory immune response and inducing a tolerant response to parasite antigens. The time of duration and the intensity of the inflammatory agent determine different degrees or phases of transformation in tissues (Zaccone et al., 2006).

Effect of probiotic administration on the immune response: a systematic review of experimental models in rats

The probiotic influence on the immune system, especially under pathogenic challenge conditions, still remains controversial. To address this, a systematic review of current studies concerning the efficacy of probiotics on the immune response of rats subjected to experimental challenges was conducted. The survey was conducted using PubMed, ISI Web of Science and Scielo databases. Only studies which tested probiotics in vivo in rats were included. The experimental design, methodological quality, and results of the articles were analyzed. In total 21 articles were selected for this study. The most commonly used microorganisms in the experiments were those of the genus Lactobacillus, which was reported in 12 articles. The second most often used genus was Bifidobacterium (B. animalis and B.longum). In general, the probiotics use against experimental pathogenic challenges was successful: 86% of the selected articles reported a beneficial effect on the immune response associated with the use of probiotics.

A directed approach for the identification of transcripts harbouring the spliced leader sequence and the effect of trans-splicing knockdown in Schistosoma mansoni.

Schistosomiasis is a major neglected tropical disease caused by trematodes from the genus Schistosoma. Because schistosomes exhibit a complex life cycle and numerous mechanisms for regulating gene expression, it is believed that spliced leader (SL) trans-splicing could play an important role in the biology of these parasites. The purpose of this study was to investigate the function of trans-splicing in Schistosoma mansoni through analysis of genes that may be regulated by this mechanism and via silencing SL-containing transcripts through RNA interference. Here, we report our analysis of SL transcript-enriched cDNA libraries from different S. mansoni life stages. Our results show that the trans-splicing mechanism is apparently not associated with specific genes, subcellular localisations or life stages. In cross-species comparisons, even though the sets of genes that are subject to SL trans-splicing regulation appear to differ between organisms, several commonly shared orthologues were observed. Knockdown of trans-spliced transcripts in sporocysts resulted in a systemic reduction of the expression levels of all tested trans-spliced transcripts; however, the only phenotypic effect observed was diminished larval size. Further studies involving the findings from this work will provide new insights into the role of trans-splicing in the biology of S. mansoni and other organisms. All Expressed Sequence Tags generated in this study were submitted to dbEST as five different libraries. The accessions for each library and for the individual sequences are as follows: (i) adult worms of mixed sexes (LIBEST_027999: JZ139310 - JZ139779), (ii) female adult worms (LIBEST_028000: JZ139780 - JZ140379), (iii) male adult worms (LIBEST_028001: JZ140380 - JZ141002), (iv) eggs (LIBEST_028002: JZ141003 - JZ141497) and (v) schistosomula (LIBEST_028003: JZ141498 - JZ141974).

Captura de Desmodus rotundus em regiões de mata e manguezais do Estado do Maranhão: um estudo longitudinal

The aim of the study was to investigate the number of captures and the control of the common vampire bat Desmodus rotundus on small farms in the municipality of Cedral, State of Maranhao, Brazil. The area was chosen because the highest number of captures in Maranhao was made there around corrals. Official control is accomplished by applying warfarin 2%, a vampiricid gel, on captured bats. In this study, control records of captured hematophagous bats were analyzed, and a questionnaire was applied in the field to identify areas with the highest number of captures. From 2005 to 2010, 223 captures in 101 farms were studied; in 190 of them existed control with application of warfarin 2% gel on the bats.. There was a total of 344 attacked livestock out of 754 exposed animals, mostly cattle (49%), followed by horses (18%), poultry (15%), pigs (9%) and goats (8%). After 6 years, the proportion of captured male and female bats was 1.08 to 1.00, compared to 1.00 to 1.21 in the first year, what demonstrates that the treatment was more effective in females. Within three years, there was control in the number of bats in 95% of the farms, after 1 to 6 captures. The main attacked area of the animal bodies was the neck. Only 57% of the owners vaccinated their livestock. The present study concluded that (1) the control with capture of bats in corrals was effective, (2) but it is prudent to monitor the area during the first 3 months after the end of control, (3) the number of captured bats was similar to the number of recent bites, and (4) D. rotundus could attack any domestic animal, with little predilection for poultry.

Oat beta-glucan as a dietary supplement for dogs

The aim of this study was to evaluate the effects of oat beta-glucan supplementation on metabolic, physiological, immunological and nutritional variables in adult dogs. Fourteen dogs were fed a control diet or a diet supplemented with 1% beta-glucan during 71 days. Serum concentrations of glucose, total cholesterol and lipoprotein fractions, as well as plasma concentrations of peptide YY and ghrelin, were determined. In addition, coefficient of total tract apparent macronutrient digestibility (CTTAD), food intake and fecal output, score, and pH were evaluated. For evaluation of immunological variables, serum concentrations of interleukin-4 and interferon gamma were determined on days 0, 57 and 71, which corresponded to blood collection prior to beta-glucan supplementation, and at 7 and 14 days post first and second dose of vaccination (Pneumodog®, Merial, Campinas, Brazil), respectively. Animals fed the supplemented diet showed (P<0.05) lower serum concentrations of total cholesterol and low and very low density lipoproteins, lower coefficients of total tract apparent digestibility of dry matter, organic matter, mineral matter and ether extract, higher fecal output and lower fecal consistency, as well as a tendency (P = 0.07) of decreasing the coefficient of total tract apparent digestibility of crude protein. Moreover, the supplemented diet resulted in lower number of red blood cells, hematocrit percentage and hemoglobin concentration 21 days post-vaccination as well as lower serum concentration of interleukin-4 seven days post-vaccination (P<0.05). It is concluded that oat beta-glucan extract can be used as a dietary supplement for dogs at a dose of 10 g/kg of food, being effective in reducing blood concentrations of total cholesterol, LDL-c and VLDL-c as well as CTTAD of nutrients, demonstrating a potential to be used in the feeding of obese animals. In addition, by reducing the predominance of a Th2 response, oat beta-glucan can positively modulate the vaccine response of animals.