Pathological and parasitological aspects of the peacock (Pavo cristatus) infection by Tanaisia(Paratanaisia)bragai

Abstract:Trematodes belonging to the family Eucotylidae, including Tanaisia(Paratanaisia)bragaiSantos, 1934are parasites of the kidney and ureter that affect several species of domestic and wild birds. Tanaisia bragaiis considered a low pathogenic parasite, but high worm burdens may determine clinical complications, including signs of apathy, weight loss, diarrhea and death. This paper describes the first report of infection by T. bragai in peacocks (Pavo cristatus), which constitutes a new host record and offers data on the lesions associated to this parasitism, although the degree of pathogenicity and parasite load may be considered mild. These birds did not exhibit clinical signs of parasitism. The macroscopic exam revealed discreet yellow spots on the liver. In the histological sections of the kidney, specimens of T. bragai were found in the collecting ducts, which were markedly dilated, with a thickened wall. Other findings included a mild inflammatory reaction in the wall of the ducts (but sometimes absent), flattening of lining epithelial cells and small, multifocal points of calcification around the collecting ducts. The microscopic examination of the parasites revealed trematodes with an elongated body, well-developed sub terminal oral sucker, pharynx present, short esophagus, cecum somewhat undulating or not, with blind end, testes symmetrical, equatorial, irregular in shape or slightly lobed, vitelline fields extending in both pre-ovarian and post ovarian fields, uterus very long, intercecal or sometimes overlapping the cecum and containing large quantities of eggs. The present findings suggest the need for further diagnostic studies on the prevalence of this trematode in peacocks as well as pathologic studies for the determination of the potential pathogenicity of this parasite in this species of bird. Moreover, infected peacocks could serve as carriers of T. bragai to be transferred to other bird species, thereby contributing to the dispersion of the parasite.

Oestrus ovis infection of grazing sheep during summer in southern Chile

Abstract: Oestrus ovis is a botfly whose larvae cause nasal myiasis, an environmental-dependent disease in small ruminants, generating acute and chronic injuries in the cranial cavities of sheep. Chile is a country of the southernmost worldwide distribution of this parasite, and there is few information about. Whence, the objective of this study was to approximate the epidemiological situation of O. ovis infection in Chilean sheep. From December 2009 to March 2010, a total of 87 samples were obtained by necropsy for skull inspection. The larvae were collected, and microscopically identified. The prevalence in the sampled sheep was 60.9%. From those that were infected, 85.7% (18/21) of sheep were 1 to 3 years old, constituting the stratum with the highest prevalence. The difference of infection in females and males was not significant. The high risk of infection seems to be dependent upon the environmental conditions of this southern region, especially during summer when the first larval stage (L1) could be found as the evidence. Therefore, the disease should be considered as a significant problem for this kind of livestock production.

Occurrence and risk factors assessment associated with Mycoplasma gallisepticum (MG) infection in chickens in the semiarid region of Pernambuco, Brazil

Abstract: The aim of the present study was to assess the occurrence of Mycoplasma gallisepticum (MG) infection and risk factors of this disease in three hundred serum samples from on 23 familiar agricultural properties in the semiarid region of the state of Pernambuco, Brazil. ELISA was used to study antibodies anti-Mycoplasma gallisepticum. The univariate analysis (chi-squared test or Fischer's exact test) followed by multivariate analysis (logistic regression) were used to assess the risk factors with two variables: management and sanity of the poultry. It was detected a frequence of 53.33% (157/300) of the birds were positive for MG, with 100% foci. The risk factors confirmed by multivariate analysis, in the present study, were the presence of other poultry species on the property, including Numida meleagris (OR=2.22; p=0.005), parrots (OR=1.72; p=0.027), and of passerines (OR=1.88; p=0.007). These results showed that Mycoplasma gallisepticum infection is endemic among backyard poultry in the semiarid region of the state of Pernambuco. These birds could be a source of infection for other wild or domestic poultry. . This is the first report of the occurrence of avian mycoplasmosis in backyard poultry in the state of Pernambuco in northeastern Brazil. The risk factors identified should serve as a parameter for the health authorities to seek solutions related to controlling the disease.

Relationship of cytokines and cytokine signaling to immunodeficiency disorders in the mouse

The contributions of cytokines to the development and progression of disease in a mouse model of retrovirus-induced immunodeficiency (MAIDS) are controversial. Some studies have indicated an etiologic role for type 2 cytokines, while others have emphasized the importance of type 1 cytokines. We have used mice deficient in expression of IL-4, IL-10, IL-4 and IL-10, IFN-g, or ICSBP - a transcriptional protein involved in IFN signaling - to examine their contributions to this disorder. Our results demonstrate that expression of type 2 cytokines is an epiphenomenon of infection and that IFN-g is a driving force in disease progression. In addition, exogenously administered IL-12 prevents many manifestations of disease while blocking retrovirus expression. Interruption of the IFN signaling pathways in ICSBP-/- mice blocks induction of MAIDS. Predictably, ICSBP-deficient mice exhibit impaired responses to challenge with several other viruses. This immunodeficiency is associated with impaired production of IFN-g and IL-12. Unexpectedly, however, the ICSBP-/- mice also develop a syndrome with many similarities to chronic myelogenous leukemia in humans. The chronic phase of this disease is followed by a fatal blast crisis characterized by clonal expansions of undifferentiated cells. ICSBP is thus an important determinant of hematopoietic growth and differentiation as well as a prominent signaling molecule for IFNs

The role of IL-12 in experimental Trypanosoma cruzi infection

Host resistance to Trypanosoma cruzi infection is dependent on both natural and acquired immune responses. During the early acute phase of infection in mice, natural killer (NK) cell-derived IFN-g is involved in controlling intracellular parasite replication, mainly through the induction of nitric oxide biosynthesis by activated macrophages. We have shown that IL-12, a powerful inducer of IFN-g production by NK cells, is synthesized soon after trypomastigote-macrophage interaction. The role of IL-12 in the control of T. cruzi infection in vivo was determined by treating infected mice with anti-IL-12 monoclonal antibody (mAb) and analyzing both parasitemia and mortality during the acute phase of infection. The anti-IL-12 mAb-treated mice had higher levels of parasitemia and mortality compared to control mice. Also, treatment of infected mice with mAb specific for IFN-g or TNF-a inhibited the protective effect of exogenous IL-12. On the other hand, TGF-ß and IL-10 produced by infected macrophages inhibited the induction and effects of IL-12. Therefore, while IL-12, TNF-a and IFN-g correlate with resistance to T. cruzi infection, TGF-ß and IL-10 promote susceptibility. These results provide support for a role of innate immunity in the control of T. cruzi infection. In addition to its protective role, IL-12 may also be involved in the modulation of T. cruzi-induced myocarditis, since treatment of infected mice with IL-12 or anti-IL-12 mAb leads to an enhanced or decreased inflammatory infiltrate in the heart, respectively. Understanding the role of the cytokines produced during the acute phase of T. cruzi infection and their involvement in protection and pathogenesis would be essential to devise new vaccines or therapies.

Effect of the injection of an extract of Ascaris suum on macrophage activation during the early phase of Mycobacterium bovis BCG infection in C57Bl/6 mice

Injection of an Ascaris suum extract (Asc) affects both the humoral and cellular immune responses to unrelated antigens when it is co-administered with these antigens. In the present study we evaluated the effect of Asc on macrophage activation in the early phase of Mycobacterium bovis BCG (Pasteur strain TMCC 1173) infection in C57Bl/6 mice. C57Bl/6 mice were injected intraperitoneally (ip) with 0.1 mg BCG (BCG group) or BCG plus 1 mg Asc (BCG + Asc group). The peritoneal exudates were obtained at 2, 7 and 14 days after infection. The numbers of IFN-g-secreting cells were assessed by the ELISPOT assay. Nitric oxide (NO) production was measured by the Griess method and by the evaluation of NADPH diaphorase activity in the peritoneal exudates. The administration of Asc extract increased NADPH diaphorase activity (2 days: control = 0, BCG = 7%, BCG + Asc = 13%, and Asc = 4%; 7 days: control = 4, BCG = 13%, BCG + Asc = 21%, and Asc = 4.5%) and TNF-a levels (mean ± SD; 2 days: control = 0, BCG = 169 ± 13, BCG + Asc = 202 ± 37, and Asc = 0; 7 days: control = 0, BCG = 545 ± 15.5, BCG + Asc = 2206 ± 160.6, and Asc = 126 ± 26; 14 days: control = 10 ± 1.45, BCG = 9 ± 1.15, BCG + Asc = 126 ± 18, and Asc = 880 ± 47.67 pg/ml) in the early phase of BCG infection. Low levels of NO production were detected at 2 and 7 days after BCG infection, increasing at 14 days (mean ± SD; 2 days: control = 0, BCG = 3.7 ± 1.59, BCG + Asc = 0.82 ± 0.005, Asc = 0.48 ± 0.33; 7 days: control = 0, BCG = 2.78 ± 1.54, BCG + Asc = 3.07 ± 1.05, Asc = 0; 14 days: control = 0, BCG = 9.05 ± 0.53, BCG + Asc = 9.61 ± 0.81, Asc = 10.5 ± 0.2 (2 x 106) cells/ml). Furthermore, we also observed that Asc co-injection induced a decrease of BCG-colony-forming units (CFU) in the spleens of BCG-infected mice during the first week of infection (mean ± SD; 2 days: BCG = 1.13 ± 0.07 and BCG + Asc = 0.798 ± 0.305; 7 days: BCG = 1.375 ± 0.194 and BCG + Asc = 0.548 ± 0.0226; 14 days: BCG = 0.473 ± 0.184 and BCG + Asc = 0.675 ± 0.065 (x 102) CFU). The present data suggest that Asc induces the enhancement of the immune response in the early phase of BCG infection.

The role of complement in the early phase of Leishmania (Leishmania) amazonensis infection in BALB/c mice

Complement-depleted and -non-depleted BALB/c mice were inoculated with Leishmania (Leishmania) amazonensis promastigotes into the hind footpad to study the role of the complement system in cutaneous leishmaniasis. Total serum complement activity was measured by hemolytic assay and C3 fragment deposit at the inoculation site was determined by direct immunofluorescence in the early period of infection, i.e., at 3, 24, 48 h and 7 days post-infection. The inflammatory reaction and the parasite burden were evaluated in the skin lesion at 7 and 30 days post-infection. Total serum complement activity decreased in the early phase of infection, from 3 to 24 h, in non-depleted mice compared to non-infected and non-depleted mice. C3 fragment deposit at the site of parasite inoculation was present throughout the period of infection in non-depleted mice. In contrast, no C3 fragment deposit was observed at the inoculation site in complement-depleted mice. Complement-depleted mice showed a significant decrease in the inflammatory response and a significant increase in the number of parasites (70.0 ± 5.3 vs 5.3 ± 1.5) at 7 days of infection (P < 0.05). A higher number of parasites were also present at 30 days of infection at the inoculation site of complement-depleted mice (78.5 ± 24.9 vs 6.3 ± 5.7). These experiments indicate that complement has an important role at the beginning of experimental cutaneous leishmaniasis caused by L. (L.) amazonensis by controlling the number of parasites in the lesion.

An experimental model of mycobacterial infection under corneal flaps

In order to develop a new experimental animal model of infection with Mycobacterium chelonae in keratomileusis, we conducted a double-blind prospective study on 24 adult male New Zealand rabbits. One eye of each rabbit was submitted to automatic lamellar keratotomy with the automatic corneal shaper under general anesthesia. Eyes were immunosuppressed by a single local injection of methyl prednisolone. Twelve animals were inoculated into the keratomileusis interface with 1 µl of 10(6) heat-inactivated bacteria (heat-inactivated inoculum controls) and 12 with 1 µl of 10(6) live bacteria. Trimethoprim drops (0.1%, w/v) were used as prophylaxis for the surgical procedure every 4 h (50 µl, qid). Animals were examined by 2 observers under a slit lamp on the 1st, 3rd, 5th, 7th, 11th, 16th, and 23rd postoperative days. Slit lamp photographs were taken to document clinical signs. Animals were sacrificed when corneal disease was detected and corneal samples were taken for microbiological analysis. Eleven of 12 experimental rabbits developed corneal disease, and M. chelonae could be isolated from nine rabbits. Eleven of the 12 controls receiving a heat-inactivated inoculum did not develop corneal disease. M. chelonae was not isolated from any of the control rabbits receiving a heat-inactivated inoculum, or from the healthy cornea of control rabbits. Corneal infection by M. chelonae was successfully induced in rabbits submitted to keratomileusis. To our knowledge, this is the first animal model of M. chelonae infection following corneal flaps for refractive surgery to be described in the literature and can be used for the analysis of therapeutic responses.

Effects of autacoid inhibitors and of an antagonist on malaria infection in mice

The effects of p-chlorophenylalanine, an inhibitor of serotonin synthesis, indomethacin, an inhibitor of prostaglandin synthesis, cyproheptadine, a serotonin, bradykinin and histamine antagonist, were assessed separately and in combination with chloroquine (CQ) in Vom strains of Swiss albino mice (18-22 g) of either sex infected intraperitoneally with 1 x 10(7) Plasmodium yoelii nigeriensis-induced malaria. As prophylactic, these agents reduced from 31.9 ± 4.5 to 16.1 ± 8.1% the level of parasitemia relative to control but had no appreciable activity as curative agents when administered subcutaneously once daily for 4 days after 72 h of parasites innoculum in vivo. However, CQ alone and the combination of these agents with CQ in curative and prophylactic treatments significantly reduced (from 50.3 ± 5.8 to 4.9 ± 0.75%) the level of parasitemia (P < 0.05), which was taken only once 72 h after the parasites innoculum. The prophylactic result was shown to produce better results than the curative treatment. The data indicate that inhibitors and an antagonist can reduce the parasitemia load (the extent of damage and the severity of infection) as well as enhance the effects of CQ when combined with it for malaria therapy. The study reveals that the production of autacoids in established infection renders autacoid inhibitors and an antagonist ineffective for radical cure in malarial mice; however, selective inhibition of local hormones implicated in the pathological manifestations of malaria infection by autacoid inhibitors and an antagonist may be a possible pathway to reduce the severity of infection and the associated tissue damage and to enhance the efficacy of available anti-malarials.

Evaluation of polymethylmethacrylate as ocular implant in rabbits subjected to evisceration

Spheres of different types of material are used for the replacement of lost volume after removal of the eye bulb or its content to prevent contraction of the orbital cavity. The aim of this study was to evaluate the scope of polymethylmethacrylate (PMMA) used as intraocular implant in eviscerated rabbit eye. Twelve New Zealand rabbits underwent unilateral evisceration of the left eye, with subsequent implantation of PMMA sphere 12 mm in diameter. Clinical evaluation was performed daily during the first 15 days after surgery and every 15 days until the end of the study period (180 days). For the histopathological analysis, three animals per trial underwent enucleation at 15, 45, 90 and 180 days after evisceration. There was no wound dehiscence, signs of infection or implant extrusion in any animal throughout the study period. Histological examination revealed the formation of fibrovascular tissue around the implants. The PMMA behaved as inert and non-integrable.

Antibodies against Bovine herpesvirus 1 in dairy herds in the state of Espirito Santo, Brasil

Bovine herpesvirus 1 (BoHV-1) causes major losses in worldwide livestock, affecting the respiratory and reproductive tracts of bovine. In the past decades, the number of cases in Brazil has been gradually increasing. Therefore, it is important to assess the distribution of infection in different regions of the country. In the state of Espírito Santo (ES) the BoHV 1 infection rate in dairy cattle herds is unknown. Thus, the aim of this study was to detect neutralizing antibodies against BoHV-1 in serum samples from 1,161 non-vaccinated cows from 59 dairy cattle herds in 23 municipalities of the Metropolitan, North, Northwest and South macro-regions. The identification of seropositive cows was evaluated by the virus neutralization test. The results showed that of all serum samples evaluated 775 (66.75%) had neutralizing antibodies against BoHV-1. Moreover, all herds were found positive; however, the percentage of positive cows varied among regions; 49.06%, 62.15%, 67.21% and 80.04% for the Metropolitan, South, North and Northwest macro-regions, respectively. In this study, the results clearly indicate the dissemination of the viral agent in dairy cattle in the ES state, requiring the monitoring and control of diseases related to BoHV-1 infection.

The epidemiology and control of schistosomiasis mansoni where Biomphalaria tenagophila is the snail host

The epidemiology and control of schistosomiasis mansoni in the Municipality of Pedro de Toledo (State of S. Paulo, Brazil) since 1980, has been studied. In 1980 the prevalence evaluated by stool exams (Kato-Katz method) was 22.8% and no statistical difference at 5.0% level was observed between rural and urban zones. The intensity of infection was low (58.5 eggs/g of faeces); the highest prevalence and intensity of infection rates were observed within the group of from 5 to 29 years of age, respectively. The transmission of schistosomiasis usually occurred during leisure time. The majority of the carriers of the parasite were asymptomatic. Of the B. tenagophila examined only 0.4% were found to be infected. The control programme has been intensified from 1981 on resulting in a sharp decrease in the prevalence from 22.8% in 1980 to 6% at the present time. This result shows that, in spite of the control programme there is a residual human prevalence. A beginning has been made on the investigation into the possible causes of this residual prevalence (6.0% was maintained through out 1987).

A theoretical model of the evolution of virulence in sexually transmitted HIV/AIDS

INTRODUCTION: The evolution of virulence in host-parasite relationships has been the subject of several publications. In the case of HIV virulence, some authors suggest that the evolution of HIV virulence correlates with the rate of acquisition of new sexual partners. In contrast some other authors argue that the level of HIV virulence is independent of the sexual activity of the host population. METHODS: Provide a mathematical model for the study of the potential influence of human sexual behaviour on the evolution of virulence of HIV is provided. RESULTS: The results indicated that, when the probability of acquisition of infection is a function both of the sexual activity and of the virulence level of HIV strains, the evolution of HIV virulence correlates positively with the rate of acquisition of new sexual partners. CONCLUSION: It is concluded that in the case of a host population with a low (high) rate of exchange of sexual partners the evolution of HIV virulence is such that the less (more) virulent strain prevails.

Age transition of tuberculosis incidence and mortality in Brazil

OBJECTIVE: Before the Aids pandemic, demographic transition and control programs prompted a shift in the age of incidence of tuberculosis from adults to older people in many countries. The objective of the study is to evaluate this transition in Brazil. METHODS: Tuberculosis incidence and mortality data from the Ministry of Health and population data from the Brazilian Bureau of Statistics were used to calculate age-specific incidence and mortality rates and medians. RESULTS: Among reported cases, the proportion of older people increased from 10.5% to 12% and the median age from 38 to 41 years between the period of 1986 and 1996. The smallest decrease in the incidence rate occurred in the 30--49 and 60+ age groups. The median age of death increased from 53 to 55 years between 1980 and 1996. The general decline in mortality rates from 1986 to 1991 became less evident in the 30+ age group during the period of 1991 to 1996. A direct correlation between age and mortality rates was observed. The largest proportion of bacteriologically unconfirmed cases occurred in older individuals. CONCLUSIONS: The incidence of tuberculosis has begun to shift to the older population. This shift results from the decline in the annual risk of infection as well as the demographic transition. An increase in reactivation tuberculosis in older people is expected, since this population will grow from 5% to 14% of the Brazilian population over the next 50 years. A progressive reduction in HIV-related cases in adults will most likely occur. The difficulty in diagnosing tuberculosis in old age leads to increased mortality.

Seroprevalence of human parvovirus B19 in a suburban population in São Paulo, Brazil

OBJECTIVE: To analyze the prevalence of IgG antibodies to human parvovirus B19. METHODS: Cross-sectional study in a suburban community in São Paulo, Southeastern Brazil, between November 1990 and January 1991. Randomly selected (N=435) representative samples of sera were collected from healthy children older than 15 days old and adults up to 40 years old. IgG antibodies were detected using ELISA. RESULTS: High prevalence of IgG antibodies to B19 parvovirus was found in 87% of newborns. The prevalence of maternally derived IgG antibodies exponentially plunged up to the 19th month of age. Low prevalence of antibodies was found in the first 4 years of life, increasing up to 72% in those aged 31-40 years. It was estimated that the average age of first infection in this population is 21 ± 7 years old and the optimal age for vaccination with a hypothetical vaccine would be 1 year of age. CONCLUSIONS: Parvovirus B19 IgG antibody prevalence was high in newborns and those aged 31-40 years. The analysis by age groups showed a pattern similar to that found in previous studies, i.e., low prevalence of infection in children that increases with age.