Detection of the acute phase of abdominal angiostrongyliasis with a parasite-specific IgG enzyme linked immunosorbent assay

Angiostrongylus costaricensis may cause intestinal lesions of varied severity when it accidentally infects man in Central and South America. First-stage larvae have never been detected in stools. Therefore, a parasite-specific IgG ELISA was evaluated for the determination of the acute phase of infection. The specificity and the sensitivity of the immunoassay was shown to be 76.2% and 91.1%, respectively. Eight serum samples taken from patients with histopathological diagnosis, at different time points (3 to 15 months) after surgical treatment, showed a sharp and early decline in antibody reactivity. The titration of anti-A. costaricensis antibodies has proved to be a useful method for the diagnosis of acute abdominal angiostrongyliasis.

Specific situations related to acute schistosomiasis in Pernambuco, Brazil

The present work reports on two epidemiological episodes resulting in acute schistosomiasis involving wealthy persons living in the State of Pernambuco, Brazil. The authors discuss the epidemiological, clinical and serologic characteristics of the acute infections and also the way in which the conditions for transmission occurred.

Some Aspects of Protozoan Infections in Immunocompromised Patients: A Review

Protozoa are among the most important pathogens that can cause infections in immunocompromised hosts. These microorganisms particularly infect individuals with impaired cellular immunity, such as those with hematological neoplasias, renal or heart transplant patients, patients using high doses of corticosteroids, and patients with acquired immunodeficiency syndrome. The protozoa that most frequently cause disease in immunocompromised patients are Toxoplasma gondii, Trypanosoma cruzi, different Leishmania species, and Cryptosporidium parvum; the first two species cause severe acute meningoencephalitis and acute myocarditis, Leishmania sp. causes mucocutaneous or visceral disease, and Cryptosporidium can lead to chronic diarrhea with hepatobiliary involvement. Various serological, parasitological, histological and molecular methods for the diagnosis of these infections are currently available and early institution of specific therapy for each of these organisms is a basic measure to reduce the morbidity and mortality associated with these infections.

Acute inflammatory response in the stomach of BALB/c mice challenged with coccoidal Helicobacter pylori

An experimental murine model was used to verify the viability and pathogenicity of coccoid Helicobacter pylori. For this purpose, 27 BALB/c mice were inoculated intragastrically with 1 ml broth culture (10(8)organisms/ml) of a coccoid H. pylori clinical isolate. The animals were divided into two groups. Nine were infected on a one-time basis (GA1) and 18 were infected on two consecutive days (GA2). Other 27 mice were inoculated with Brucella broth and divided in the same way; they composed the control group. Mice were killed at 2, 3, 7, 14 and 21 days post inoculation (pi). Fragments of stomach and duodenum were collected, fixed with 12% formalin and stained by hematoxilin-eosin and Giemsa for histopathological examination. Until the 14th()day, only reinfected mice had mild-to-moderate inflammatory infiltrate in the stomach. The infiltration was predominantly lymphomonocytic, although plasma cells and eosinophils could be seen. However, at 21st day, severe eosinophilic infiltration was present in the lamina propria and submucosa of gastric corpus. In subgroup GA1, animals presented lymphomonocytic infiltration in the stomach from 14th()day pi. Our results showed that coccoid H. pylori was able to induce an acute inflammatory response in stomach of reinfected mice since the initial periods of infection.

Acute schistosomiasis outbreak in the metropolitan area of Belo Horizonte, Minas Gerais: alert about the risk of unnoticed transmission increased by growing rural tourism

The present article describes the occurrence of 17 cases of acute schistosomiasis in the metropolitan area of Belo Horizonte, state of Minas Gerais, Brazil. All individuals affected took a bath in a swimming pool of a holiday resort that was provided with water from a nearby brook. The apparently clean water and the absence of snails in the pool gave the wrong impression that there was no risk for infection. During a malacological survey at the site snails of the species Biomphalaria glabrata were found and tested positive for Schistosoma mansoni. All the patients live in the middle-class area of Barreiro, metropolitan area of Belo Horizonte and have medium grade school education. The difficulties in establishing the right diagnosis is expressed by the search for medical attention in 17 different medical facilities, the wide range of laboratory test and the inadequate treatment administration. A lack of knowledge about the disease was found in all groups studied. The booming rural tourism in endemic areas is identified as a probable risk factor for infection, especially for individuals of the non-immune middle and upper class parts of the society in urban centers. Special attention is given to a multidisciplinary approach to the complex issue of disease control and prevention.

Virulence markers and antimicrobial susceptibility of bacteria of the Bacteroides fragilis group isolated from stool of children with diarrhea in São Paulo, Brazil

Bacteroides fragilis has been isolated from several human and non-human monomicrobial and mixed infections. In this study, some virulence markers and the antimicrobial susceptibility of bacteria of the B. fragilis group isolated from children's stools were evaluated. All the 64 isolates showed the following characteristics: capsulated, beta-hemolytic, hydrophilic, and serum-resistant. Only, 24 (37.5%) strains were resistant at 60ºC, for 30 min, and among them, 12 (18.75%) were resistant at 60ºC, for 60 min. Also, none strain was resistant at 100ºC. Four strains were able to hemagglutinate erythrocytes and D-mannose, D-galactose, D-arabinose, and D-xylose inhibited hemagglutination in 2 B. fragilis strains (p76a, p76b). The hemagglutination in the strain B. uniformis p3-2 was inhibited by D-xylose and D-galactose. The bft gene detection and the enterotoxin production were observed only in 13 EF-enterotoxigenic species. Fragilysin activity was confirmed on HT-29 cells. The antimicrobial determination confirmed that both imipenem and metronidazole were efficient against B. fragilis species; all the strains were resistant to lead and nickel. Plasmids of 2.9, 4.4, 4.8, and 8.9 kb were observed in 6 tested strains. These results show the values of the species identification from clinical infections, as well as of the periodic evaluation of the resistance patterns of the B. fragilis group at Brazilian medical institutions.

Evaluation of tests based on the antibody response to keyhole limpet haemocyanin and soluble egg antigen to differentiate acute and chronic human schistosomiasis mansoni

Specific IgG and IgM responses to soluble egg antigen (SEA) and keyhole limpet haemocyanin (KLH) were measured by ELISA in patients with acute and chronic schistosomiasis. The tests based upon IgM and IgG antibodies responses to KLH presented the best diagnostic discrimination, and can be used in conjunction with clinical and epidemiological data to the differential diagnosis of acute schistosomiasis.

Trypanosoma cruzi isolates from Mexican and Guatemalan acute and chronic chagasic cardiopathy patients belong to Trypanosoma cruzi I

Trypanosoma cruzi is classified into two major groups named T. cruzi I and T. cruzi II. In the present work we analyzed 16 stocks isolated from human cases and four isolated from triatomines from diverse geographical origins (Mexico and Guatemala). From human cases four were acute cases, six indeterminates, and six from chronic chagasic cardiophatic patients with diagnosis of dilated cardiomyopathy established based on the left-ventricular end systolic dimension and cardiothoracic ratio on chest X-radiography and impaired contracting ventricle and different degree conduction/rhythm aberrations. DNA samples were analyzed based on mini-exon (ME) polymorphism, using a pool of three oligonucleotide for the amplification of specific intergenic region of T. cruzi ME gene. All the Mexican and Guatemalan isolates regardless their host or vector origin generated a 350 bp amplification product. In conclusion T. cruzi I is dominant in Mexico and Guatemala even in acute and chronic chagasic cardiopathy patients. To our knowledge, this is the first study describing predominance of T. cruzi I in human infection for North and Central America.

Effects of antifolates - co-trimoxazole and pyrimethamine-sulfadoxine - on gametocytes in children with acute, symptomatic, uncomplicated, Plasmodium falciparum malaria

Antimalarial drugs including the antifolate, pyrimethamine-sulfadoxine (PS), can modulate the prevalence and intensities of gametocytaemia following treatment of acute malaria infections. They may also directly influence the transmission and spread of drug insensitivity. Little is known of the effects of co-trimoxazole (Co-T), another antifolate antimalarial, on gametocytes in children with acute malaria infections. We compared the effects of Co-T and PS on the prevalence and intensities of gametocytaemia and gametocyte sex ratios in 102 children aged 0.5-12 years presenting with acute and uncomplicated falciparum malaria. Compared to pre-treatment, both drugs significantly increased gametocyte carriage post-initiation of treatment. However, gametocyte carriage was significantly lower on day 14 in those treated with Co-T than PS. Significant increase in gametocytaemia with time occurred in PS - but not Co-T-treated children. Kaplan-Meier survival curve of the cumulative probability of remaining gametocyte-free in children who were agametocytaemic at enrolment showed that by day 7 of follow up, children treated with PS had a significantly higher propensity to have developed gametocytes than in Co-T-treated children (Log-rank statistic 5.35, df = 1, P = 0.02). Gametocyte sex ratio changes were similar following treatment with both drugs. PS and Co-T treatment of acute malaria infections in children from this endemic area is associated with significant increases in prevalence and intensities of gametocytaemia but these effects are more marked in those treated with PS than Co-T.

Epithelial cell signaling responses to enterohemorrhagic Escherichia coli infection

Enterohemorrhagic Escherichia coli, including the serotype O157:H7 that is most commonly identified with human disease, cause both sporadic cases and outbreaks of non-bloody diarrhea and hemorrhagic colitis. In about 10% of infected subjects, the hemolytic uremic syndrome (hemolytic anemic, thrombocytopenia, and acute renal failure) develops, likely as a consequence of systemic spread of bacterial-derived toxins variously referred to as Shiga-like toxin, Shiga toxin, and Verotoxin. Increasing evidence points to a complex interplay between bacterial products - for example, adhesins and toxins - and host signal transduction pathways in mediating responses to infection. Identification of critical signaling pathways could result in the development of novel strategies for intervention to both prevent and treat this microbial infection in humans.

Frequency of viruses associated with acute respiratory infections in children younger than five years of age at a locality of Mexico City

A locality in the district of Tlalpan, Mexico City, was selected in order to identify the viral agents in children younger than 5 years of age with acute respiratory infection (ARI). A total of 300 children were randomly selected and were included in this study for a period of 13 months. During this period nasopharyngeal exudates were collected for the isolation of viral agents. Monoclonal fluorescent antibodies were used for viral identification after cell culture. Viral infection was detected in 65% of the specimens. The respiratory syncytial virus (RSV) was the most common virus agent detected. Children required an average of two consultations during the study period. Two high incidence peaks were observed, one during the summer and the other during winter; the most frequent viruses during these seasons were influenza A and RSV, respectively. The largest number of viruses was isolated in the group of children between 1 and 2 years of age and in the group between 4 and 5 years of age. This study demonstrated the presence of ARI and of different viruses in a period of 13 months, as well as the most frequent viruses in children younger than 5 years of age from a community of Mexico City.

Respiratory viruses in children younger than five years old with acute respiratory disease from 2001 to 2004 in Uberlândia, MG, Brazil

The main viruses involved in acute respiratory diseases among children are: respiratory syncytial virus (RSV), influenzavirus (FLU), parainfluenzavirus (PIV), adenovirus (AdV), human rhinovirus (HRV), and the human metapneumovirus (hMPV). The purpose of the present study was to identify respiratory viruses that affected children younger than five years old in Uberlândia, Midwestern Brazil. Nasopharyngeal aspirates from 379 children attended at Hospital de Clínicas (HC/UFU), from 2001 to 2004, with acute respiratory disease, were collected and tested by immunofluorescence assay (IFA) to detect RSV, FLU A and B, PIV 1, 2, and 3 and AdV, and RT-PCR to detect HRV. RSV was detected in 26.4% (100/379) of samples, FLU A and B in 9.5% (36/379), PIV 1, 2 and 3 in 6.3% (24/379) and AdV in 3.7% (14/379). HRV were detected in 29.6% (112/379) of the negative and indeterminate samples tested by IFI. RSV, particularly among children less than six months of life, and HRV cases showed highest incidence. Negative samples by both IFA and RT-PCR might reflect the presence of other pathogens, such as hMPV, coronavirus, and bacteria. Laboratorial diagnosis constituted an essential instrument to determine the incidence of the most common viruses in respiratory infections among children in this region.

Schizodeme analysis of Trypanosoma cruzi Colombian strain clones isolated from the acute phase of murine infection

Colombian strain of Trypanosoma cruzi, biodeme Type III (T. cruzi I), has been cloned by micromanipulation at two phases of the acute infection: early (10 days ) and advanced (30 days). Twelve clones were obtained therefrom. Characterization by their biological and biochemical behavior showed an identity among the several clones and their parental strain, albeit with different degrees of virulence. Molecular characterization of the kinetoplast DNA (kDNA) after amplification by polymerase chain reaction revealed identical profiles of the bands from the kDNA minicircle by the analysis of restriction fragment lenght polymorphism for the isolated clones, their parental strain, and to the clones isolated at two different phases of the infection. Results suggest the predominance of a "principal clone", in the composition of the Colombian strain, responsible for the biological and biochemical behavior. However, no relationship was detected between the molecular profile of kDNA and the degree of virulence presented by the several clones.

Detection of calicivirus from fecal samples from children with acute gastroenteritis in the West Central region of Brazil

The objective of this study was to describe the circulation of caliciviruses in the West Central region of Brazil and its correlation with children's gender and age, as well as with the year and months of the sample collection. Reverse transcriptase-polymerase chain reaction was performed to detect the human calicivirus genome in 1006 fecal samples that were collected in Goiânia (n = 696) and Brasília (n = 310). Viral RNA was detected in 8.6% of the samples. No significant difference in viral prevalence was found regarding gender, age or year of the sample. However, it was observed that in Goiânia, there is a higher incidence of caliciviruses from September to March. The analysis employing three primer pairs demonstrated that the Ni/E3 or JV12/13 primer pairs, which detect norovirus (NoV), detected 41 positive samples while the 289/290 primer pair, which detects NoV or sapovirus, detected the remaining 46 samples. Calicivirus circulates in the West Central region of Brazil and for better detection of this virus it is important to use more than one primer pair. Also, we conclude that the seasonality presented by this virus is related to higher humidity in the period.

Effects of pyrimethamine-sulphadoxine, chloroquine plus chlorpheniramine, and amodiaquine plus pyrimethamine-sulphadoxine on gametocytes during and after treatment of acute, uncomplicated malaria in children

The effects of pyrimethamine-sulphadoxine (PS), chloroquine plus chlorpheniramine, a H1 receptor antagonist that reverses chloroquine resistance in Plasmodium falciparum in vitro and in vivo (CQCP), and amodiaquine plus pyrimethamine-sulphadoxine (AQPS) on gametocyte production were evaluated in 157 children with acute, symptomatic, uncomplicated falciparum malaria who were treated with these drugs. PS was significantly less effective than CQCP or AQPS at clearing asexual parasitaemia or other symptoms of malaria. Gametocyte carriage on days 3, 7, and 14 were significantly higher in those treated with PS. The ratio of the density (per µl blood) of peripheral young gametocyte (PYG), that is, < stage III to peripheral mature gametocyte (PMG), that is, stage IV and V, an index of continuing generation of gametocytes, rose to 1 by day 7 of treatment in those treated with PS, but remained consistently below 1 in the other treatment groups. PYG-PMG density ratio increased significantly from day 0-14 in those treated with PS and CQCP (chi2 = 76, P = 0.000001 and chi2 = 42.2, P = 0.00001, respectively) but decreased significantly in those treated with AQPS (chi2 = 53.2, P = 0.000001). Both PS-sensitive and -resistant infections generated PYG (18 of 29 vs 13 of 20, chi2 = 0.04, P = 0.93) but PYG was present only in those with resistant response to CQCP. Combination of PS with amodiaquine (AQ), that is, (AQPS) resulted in less production of PYG, but in this setting, PYG was not indicative of response to AQPS. These data indicate that PS enhanced production or release of young gametocytes when used alone, but generated less young gametocytes when used in combination with AQ. PYG may be used as an indicator of response to CQCP but not PS or PS-based combination drugs.