Epidemiological aspects of the Brazilian spotted fever: serological survey of dogs and horses in an endemic area in the State of São Paulo, Brazil

In order to obtain information on Brazilian spotted fever, a study in domestic animals was performed in the County of Pedreira, State of São Paulo, Brazil, where 17 human cases had been notified. Serum samples obtained from animals were tested by indirect immunofluorescence for detectable antibodies to spotted fever-group rickettsiae. Seropositivity was revealed in 12 (36.4%) of 33 dogs and seven (77.8%) of nine horses from the endemic area. For comparison, blood samples from dogs and horses from non endemic area were tested and four (12.9%) of 31 dogs and three (27.3%) of 11 horses were positive. The highest titers of antibodies by IFA (IgG > 1:1024) were found only in three dogs and six horses from endemic area. The results suggest that dogs as horses may serve as environmental sentinels for estabilishing the prevalence of foci of spotted fever in Brazil.

Epidemiological and clinical aspects of snAkebite in Belo Horizonte, Southeast Brazil

Epidemiologic and clinical aspects of 310 hospitalized snakebite patients and 310 matched controls were described, over a seven years period, from an emergency hospital in Belo Horizonte, Southeast Brazil. The diagnosis was based upon clinical picture or actual snake identification. Fifty six percent of victims were bitten by the snakes of genus Bothrops, 32.0% by Crotalus, 1.0% by Lachesis and 10.0% undetermined. During the study period, stable number of cases and marked seasonal variation were noted. In comparing cases of snakebite and controls, those from a rural area or who were involved in agricultural labor activity were identified as a high risk group, with an odds ratio (OR) of 14.7 and 6.7, respectively, in favor of being bitten. Upon treatment, snakebite patients were 13.5 times more likely to have had early anaphylactic reactions than their controls, with a higher association in the age group ³ 20 years (OR = 30.3). Increased risks were also detected for pyrexia (OR = 11.7), with a marked association in the group under 19 years old (OR = 16.6). Severe cases of snakebite are an important treatable cause of morbidity in Brazil but therapy may be potentially life threatening. The higher case-fatality ratio encountered, compared to national statistics may be due the representativeness of the more severe cases who sought hospitalization. Preventing snakebite and early referral of those who are bitten is proposed

Autochthonous acute Chagas’ disease in São Paulo State, Brazil: Epidemiological aspects

Since the beginning of the seventies the natural transmission of Chagas’ infection has been considered to be under control in the State of São Paulo and not even a case of American Trypanosomiasis, transmitted by triatomine bugs, has been detected by the epidemiological surveillance system. This situation justifies the report of a case of acute Chagas’ disease that occurred in a forest area considered free of domiciliary triatomines along the Southern seacoast of São Paulo State. In May, 1995 the presence of trypomastigote forms of Trypanosoma cruzi had been diagnosed in a retired 57 year-old male patient, born and living in Santos (São Paulo State), complaining of fever, fatigue and malaise. The patient reported that 40 days before he had participated with 17 friends in a 7-day excursion in a forest area of the municipalities of Itanhaém and Peruíbe. During this period the group had been lodged in three houses located within the forest. Eight days after the end of the excursion the patient began to have fever, malaise and fatigue. During the next 31 days he had received medical care both as an inpatient and an outpatient, without any significant improvement. After the detection of T. cruzi trypomastigotes in his blood stream the patient began to be treated with benzonidazole in a hospital but died 8 days after the beginning of treatment. The epidemiological investigation carried out showed no signs of the presence of triatomine bugs in the three houses where the group had been lodged, or any indication of Chagas' infection in other excursionists

EPIDEMIOLOGICAL SURVEY ON CANINE POPULATION WITH THE USE OF IMMUNOLEISH SKIN TEST IN ENDEMIC AREAS OF HUMAN AMERICAN CUTANEOUS LEISHMANIASIS IN THE STATE OF RIO DE JANEIRO, BRAZIL

A survey for canine tegumentary leishmaniasis (CTL) has been carried out between 1986 and 1993 in seven endemic localities for American cutaneous leishmaniasis in the State of Rio de Janeiro. 270 dogs have been examined for their clinical aspects, the development of delayed hypersensitivity (DHS) with Immunoleish antigen and with immunofluorescent antibody research of IgG (IF). 28.2% of them had ulcer lesions and 3.3% had scars. The lesions consisted of single (39.5%) and mucocutaneous lesions (31.6%), multiple cutaneous (25.0%) and mucocutaneous lesions associated with cutaneous ulcers (4.0%). Twelve (15.8%) isolates from biopsies were analyzed by zimodeme and schizodeme and identified as L. (V.) braziliensis. The overall prevalence of canine infection that was evaluated with the skin test was of 40.5% and with IF it was of 25.5%. Both tests showed a high positive rate with relation to the animals with mucosal lesions, as in the case of human mucocutaneous leishmaniasis. The comparison of the two tests showed the skin test to have a better performance although there was no statistical difference (p>0.05) between them. The proportional sensitivity and specificity was of 84.0% and 74.0%, respectively. The Immunoleish skin test and IF are useful tools to be employed in CTL field epidemiological surveys.

HEPATITIS B VIRUS INFECTION PROFILE IN CENTRAL BRAZILIAN HEMODIALYSIS POPULATION

Hepatitis B has proved to be a major health hazard in hemodialysis patients. In order to investigate the hepatitis B virus (HBV) infection profile in the hemodialysis population of Goiânia city - Central Brazil, all dialysis patients (N=282) were studied. The prevalence of any HBV marker (HBsAg, anti-HBs, and anti-HBc) was 56.7% (95% CI: 51.1-62.7), ranging from 33.3% to 77.7% depending on dialysis unit. HBV-DNA was detected in 67.6% and 88.2% of the HBsAg-positive serum samples, in 91.3% and 100% of the HBsAg/HBeAg-positive samples, and in 18.2% and 63.6% of the HBsAg/anti-HBe-reactive sera by hybridization and PCR, respectively. The length of time on hemodialysis was significantly associated with HBV seropositivity. Only 10% of the patients reported received hepatitis B vaccination. The findings of a high HBV infection prevalence in this population and the increased risk for HBV infection on long-term hemodialysis suggest the environmental transmission, emphasizing the urgent need to evaluate strategies of control and prevention followed in these units.

A clinico-epidemiological study of bites by spiders of the genus Phoneutria

From January, 1984 to December, 1996, 422 patients (ages 9 m-99 y, median 29 y) were admitted after being bitten by spiders which were brought and identified as Phoneutria spp. Most of the bites occurred at March and April months (29.2%), in the houses (54.5%), during the day (76.5%), and in the limbs (feet 40.9%, hands 34.3%). Upon hospital admission, most patients presented only local complaints, mainly pain (92.1%) and edema (33.1%) and were classified as presenting mild (89.8%), moderate (8.5%) and severe (0.5%) envenomation. Few patients (1.2%) did not present signs of envenomation. Severe accidents were only confirmed in two children (9 m, 3 y). Both developed acute pulmonary edema, and the older died 9 h after the accident. Patients more than 70 year-old had a significantly greater (p<0.05) frequency of moderate envenomations compared to the 10-70-year-old individuals. Proceedings to relief local pain were frequently performed (local anesthesia alone 32.0%, local anesthesia plus analgesics 20.6% and oral analgesics alone 25.1%). Only 2.3% of the patients (two cases classified as severe and eight as moderate, eight of them in children) were treated with i.v. antiarachnid antivenom. No antivenom early reaction was observed. In conclusion, accidents involving the genus Phoneutria are common in the region of Campinas, with the highest risk groups being children under 10 years of age and adults over 70 years of age. Cases of serious envenomation are rare (0.5%).

Epidemiological analysis of bacterial strains involved in hospital infection in a University Hospital from Brazil

Hospital infections cause an increase in morbidity and mortality of hospitalized patients with significant rise in hospital costs. The aim of this work was an epidemiological analysis of hospital infection cases occurred in a public University Hospital in Rio de Janeiro. Hence, 238 strains were isolated from 14 different clinical materials of 166 patients hospitalized in the period between August 1995 and July 1997. The average age of the patients was 33.4 years, 72.9% used antimicrobials before having a positive culture. The most common risk conditions were surgery (19.3%), positive HIV or AIDS (18.1%) and lung disease (16.9%). 24 different bacterial species were identified, S. aureus (21%) and P. aeruginosa (18.5%) were predominant. Among 50 S. aureus isolated strains 36% were classified as MRSA (Methicillin Resistant S. aureus). The Gram negative bacteria presented high resistance to aminoglycosides and cephalosporins. A diarrhea outbreak, detected in high-risk neonatology ward, was caused by Salmonella serovar Infantis strain, with high antimicrobial resistance and a plasmid of high molecular weight (98Mda) containing virulence genes and positive for R factor.

Biotyping, serotyping and ribotyping as epidemiological tools in the evaluation of Acinetobacter baumannii dissemination in hospital units, Sorocaba, São Paulo, Brazil

Dissemination of Acinetobacter baumannii strains in different units of a hospital in Sorocaba, São Paulo, Brazil was evaluated over a period of two years. By using biotyping, serotyping and ribotyping, 27 distinct clones were differentiated among 76 strains isolated between 1993-94, from clinical specimens of hospitalized patients. Two clones, 2:O4:A (biotype:serotype:ribotype) and 2:O29:A accounted for the majority of strains widely disseminated in the units during 1993. The introduction in the hospital setting, of a new clone, 6:O13:B, at the end of 1993 and its predominance through 1994 is discussed. Among 15 strains isolated from neonates, 6 (40%) belonged to the same clone, 2:O4:A. Interestingly, this clone was almost all recovered in neonatal intensive care unit, nursery and in pediatric unit. All strains were susceptible to imipenem and polymyxcin B. Multiresistant strains (up to 12 antimicrobial agents) accounted for 66.7% and 84.8% of the strains isolated in 1993 and in 1994, respectively.

Clinical and epidemiological features of definitive and presumed loxoscelism in São Paulo, Brazil

A retrospective study analysed 359 proven or presume cases of loxoscelism seen at the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil, between 1985 and 1996. The spider was identified in 14%. The bites occurred predominantly in the urban areas (73%) between September and February. Patients > 14 years were commonest inflicted (92%) and 41% were bitten while getting dressed. Only 11% sought medical care within the first 12 hours post bite. Cutaneous loxoscelism was the commonest form presenting (96%); commonest manifestations were: pain (76%), erythema (72%), edema with enduration (66%), ecchymosis (39%). Skin necrosis occurred in 53% of patients, most frequently seen on trunk, tigh and upper arm, and when patients seek medical care more than 72 hours after bite. Local infection was detected in 12 patients (3%). Hemolysis was confirmed in 4 cases (1.1%). Generalised cutaneous rash, fever and headache were also observed in 48% of the total of patients. None of them had acute renal failure or died. Treatment usually involved antivenom administration (66%), being associated with corticosteroids (47%) or dapsone (30%). Presumptive diagnosis of loxoscelism may be established based on clinical and epidemiological findings. Further investigations are required to prove the value of antivenom and other treatment schedules.

Clinical-epidemiological study of leptospirosis in humans and reservoirs in Yucatán, México

A leptospirosis clinical-epidemiological study was made in humans and reservoirs in the state of Yucatán, México. Interviews and serological analyses were made on 400 persons from an open population, 439 probable cases of leptospirosis and 1060 animal reservoirs (cows, pigs, dogs, rats and opossums). IgM Leptospira DipstickTM and Microscopic Agglutination Test (MAT) was used to detect human antibodies to leptospiras and serovar respectively. Leptospirosis incidence in humans was 2.2/100,000 inhab. in 1998, 0.7/100,000 in 1999 and 0.9/100,000 in 2000. Overall seroprevalence was 14.2%, relatively unchanged from seroprevalences observed 20 years ago. Highest seropositivity was found in people over 56 years of age, predominating males over females. Predominant serovars in the open population were tarassovi, hardjo, pomona and panama. Leptospirosis cases were most frequent in rural areas, and the anicteric course predominated over the icteric. The panama, icterohaemorrhagiae and pomona serovars predominated in both anicteric and icteric courses. Dogs, pigs and rodents had the highest seropositivity among the reservoirs. Contact with rodents and natural water sources were significant factors (p £ 0.05). Human cases (74%) occurred during the rainy season. It is concluded that leptospirosis is still a serious illness with important clinical and epidemiological implications in the state of Yucatán, Mexico.

Plasmid profile in oral Fusobacterium nucleatum from humans and Cebus apella monkeys

Fusobacterium nucleatum is a strict anaerobe and is indigenous of the human oral cavity. This organism is commonly recovered from different monomicrobial and mixed infections in humans and animals. In this study, the plasmid profile, the plasmid stability and the penicillin-resistance association in oral F. nucleatum isolated from periodontal patients, healthy subjects and Cebus apella monkeys were evaluated. Forty-five F. nucleatum strains from patients, 38 from healthy subjects and seven from C. apella were identified and analyzed. Plasmid extraction was performed in all the isolated strains. These elements were found in 26.7% strains from patients and one strain from C. apella. Strains from healthy subjects did not show any plasmid. Most of strains showed two plasmid bands ranging from 4 to 16 Kb, but digestions with endonucleases showed that they belonged to a single plasmid. The plasmid profile was similar and stable in human and monkey strains. Also, plasmids were classified into three groups according to size. Two strains were positive to beta-lactamase production and no plasmid DNA-hybridization with a beta-lactamase gene probe was observed, suggesting a chromosomal resistance.

Analysis of the clonal relationship among clinical isolates of Salmonella enterica serovar Infantis by different typing methods

Salmonella Infantis has been the second most common serovar in Argentina in the last two years, being isolated mostly from paediatric hospitalised patients. In order to determine the clonal relationship among Salmonella Infantis strains, we examined 15 isolates from paediatric patient faeces in Argentina (12 geographically related and 3 geographically non-related) by using antimicrobial susceptibility, plasmid profiling, repetitive extragenic palindromic (REP) PCR, enterobacterial repetitive intergenic consensus (ERIC) PCR, and low-frequency restriction analysis of chromosomal DNA by pulsed field gel electrophoresis (PFGE). Four Spanish strains were included as controls of clonal diversity in molecular techniques. Antibiotype and plasmid profile was not useful as epidemiological tools. PFGE and REP-PCR were able to discriminate between Argentinean and Spanish isolates of Salmonella Infantis allowing to detect genetically related strains in three different cities. This finding indicates that a possible spread of a clone of this serovar in the North-eastern Region of Argentina has taken place in 1998.