Maria Angélica A. M. Guimarães

Primary isolation of spotted fever group rickettsiae from Amblyomma cooperi collected from Hydrochaeris hydrochaeris in Brazil

This paper reports the first isolation of a spotted fever group rickettsia from an Amblyomma cooperi ixodid collected from a capybara (Hydrochaeris hydrochaeris) in an endemic area of spotted fever in the County of Pedreira, State of São Paulo, Brazil. Isolation was performed in Vero cell culture and submitted to immunofluorescence, using antibody from Rickettsia rickettsii-positive human serum.

Prevalence of human immunodeficiency virus drug resistance mutations and subtypes in drug-naive, infected individuals in the army health service of Rio de Janeiro, Brazil.

ABSTRACT The prevalence of mutations that confer resistance to antiretroviral drugs was examined in 56 drug-naive, human immunodeficiency virus type 1 (HIV-1)-infected individuals from the Army Health Service in Rio de Janeiro, Brazil. No primary protease inhibitor mutations were found, but secondary mutations were observed in 51.2% of the samples. Fourteen percent of the viruses had reverse transcriptase inhibitor-associated mutations. Comparative analysis of protease secondary mutations from four different time periods in drug-naive patients in the city of Rio de Janeiro has indicated constant rates for particular mutations. Changes in CD4 cell counts and HIV viral load over time in subtype B- and non-B-infected drug-naive patients were not significantly different.

Epidemiological aspects of the Brazilian spotted fever: seasonal activity of ticks collected in an endemic area in São Paulo, Brazil

Ticks were collected from vegetation and animals at monthly intervals during one year (1993-1994) in an endemic area of Brazilian spotted fever in the Country of Pedreira, State of São Paulo. Six species of ticks were identified Amblyomma cajennense, Amblyomma cooperi, Amblyomma triste, Anocentor nitens, Rhipicephalus sanguineus and Boophilus microplus. Only the first species was sufficiently numerous to permit a quantitative study with seasonal activity, although the distribution and source of capture of other species were observed and are reported. This information is correlated with the epidemiology of tick-borne rickettsiosis.

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 > or = 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 establishing the prevalence of foci of spotted fever in Brazil.

Detection of Merkel cell polyomavirus in oral samples of renal transplant recipients without Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine cancer, with approximately 80% of cases associated with Merkel cell polyomavirus (MCPyV). The lack of information concerning its occurrence in non‐MCC immunosuppressed populations led to the investigation of MCPyV DNA in saliva and oral biopsies from 60 kidney allograft recipients and 75 non‐transplanted individuals (control group). In contrast to herpesviruses, which was also investigated (CMV, HHV‐6A, and B, HHV‐7) MCPyV was detected predominantly in patients with oral lesions (gingivitis and/or periodontitis) of both transplanted and non‐transplanted groups (P = 0.016) and in the saliva of the transplanted group (P = 0.009). MCPyV co‐detection with CMV (P = 0.048), and HHV‐6 (P = 0.020) in the saliva of transplanted patients requires further investigation on a possible role of co‐infection. J Med. Virol. 85:2016–2019, 2013.

Infestation by ticks and detection of antibodies to spotted fever group rickettsiae in wild animals captured in the state of São Paulo, Brazil: A preliminary report

Since 1985 several human cases of Brazilian spotted fever, an acute infectious disease of variable severity, has been reported in the county of Pedreira, State of São Paulo. Since humans are accidental victims, the epidemiology of this tickborne rickettsiosis depends primarily on the species and ecology of the tick vector involved and its mammal hosts. Several species of ticks have been recognized as natural carries of Rickettsia rickettsii, but Amblyomma cajennense is the most important vector in Brazil. Considering the scarced available information on this rickettsiosis in Brazil, we designed a multidisciplinary project in an endemic area in Pedreira. As part of this project we attempted to determine the significance of wild animals caught near human settlements, where rickettsiosis transmission foci for active transmission had been detected (ERS Lemos et al. 1996 Mem Inst Oswaldo Cruz 91: 273-275). A total of 605 ticks were collected from 14 animals belonging to four different species (Hydrochaeris hidrochaeris, Myocastor coypus bonariensis, Rattus norvergicus and Didelphis marsupialis) (Table). These animals were caught alive in special traps and were bled from the brachium vein (capibara) or from the heart (small animals). After collecting ticks and bleeding all animals were freed in same place where they were captured. After taxonomic identification, ticks were inoculated onto fresh monolayers of Vero cells for isolation. In an effort to analyse the presence of antibodies from sera of animals, a blocking imunofluorescence test was done with antigens R. rickettsii obtained from Vero cell cultures prepared at the Center for Disease Control, Atlanta, Georgia. This modified test was used to detect blocked antibodies because FITC-labeled of some anti-wild animals immunoglobulins were difficult to produce in hyper-immunized rabbits. Serial dilutions of animal sera ranging from 1:4 to 1:64 were placed on the antigen, incubated at 37°C for 30 min, and washed in phosphate buffered saline (PBS). Next, slides were incubated with a positive human sera in a 1:20 dilution for 30 min. After this step, a goat conjugate of anti-human immunoglobulin (Ig) was used. A positive sera of horse was used as positive control. Slides were examined with a Zeiss fluorescence microscope and sera title without fluorescence was considered positive. In spite of the small number of animals, it is worth of note that ectoparasites were abundant. Furthermore, a spotted fever group rickettsia was isolated from three A. cooperi ixodids collected from one of the two seroreactive (1:16) H. hydrochaeris (capibara) (Lemos et al. 1oc. cit.). All isolation attempts from blood of wild animals were negative. To further clarify serologic results and other informations mentioned in this preliminary report, studies will continue and specific anti-wild animals reagent will be prepared, mainly anti-capibara reagent.

Detection of Astrovirus-like in diarrhoeic stool and its coexistence with Rotavirus

A clinical case is described in this paper in that a 5-month old baby girl severely malnourished and dehydrated presented a prolonged acute diarrhoea. No enteropathogenic bacteria or parasites were demonstrated. Virological study by electron microscopy (EM) showed that the patient shed both astrovirus-like and rotavirus in the watery stool as long as 12 days after the onset. Immune electron microscopy (IEM) performed with the patient serum revealed clumps of both viruses. It is suggest that this may be a case of mixed infection due to astrovirus-like and rotavirus.

A non-randomized comparative study using different doses of acyclovir to prevent herpes simplex reactivation in patients submitted to autologous stem cell transplantation

The reactivation of Herpes Simplex virus (HSV) occurs in 70% to 80% of patients submitted to autologous stem cell transplantation (ASCT); it increases the severity of chemotherapy-induced mucositis. Therefore, the use of acyclovir in ASCT patients is considered standard practice. However, the minimum dose needed to prevent reactivation is a matter of debate. We compared two doses of acyclovir in a non-randomized fashion in 59 patients submitted to ASCT: 32 patients received a dose of 125 mg/m(2) IV every six hours and the subsequent 27 patients received a dose of 60 mg/m(2) IV every six hours. Viral excretion was evaluated through weekly viral culture of oral swabs. Grade 4 mucositis was more frequent in Group 1 (p= 0.03). The reactivation rates in Groups 1 and 2 were 9% and 4%, respectively (p= 0.62, 95% confidence interval -7 - 18). Prophylaxis with reduced doses of intravenous acyclovir seems to be as effective as a higher dose in inhibiting HSV reactivation, with a significant reduction in cost. Prospective randomized studies are needed to confirm our conclusions.

Phylogenetic and structural analysis of merkel cell polyomavirus VP1 in Brazilian samples

Our understanding of the phylogenetic and structural characteristics of the Merkel Cell Polyomavirus (MCPyV) is increasing but still scarce, especially in samples originating from South America. In order to investigate the properties of MCPyV circulating in the continent in more detail, MCPyV Viral Protein 1 (VP1) sequences from five basal cell carcinoma (BCC) and four saliva samples from Brazilian individuals were evaluated from the phylogenetic and structural standpoint, along with all complete MCPyV VP1 sequences available at Genbank database so far. The VP1 phylogenetic analysis confirmed the previously reported pattern of geographic distribution of MCPyV genotypes and the complexity of the South-American clade. The nine Brazilian samples were equally distributed in the South-American (3 saliva samples); North American/European (2 BCC and 1 saliva sample); and in the African clades (3 BCC). The classification of mutations according to the functional regions of VP1 protein revealed a differentiated pattern for South-American sequences, with higher number of mutations on the neutralizing epitope loops and lower on the region of C-terminus, responsible for capsid formation, when compared to other continents. In conclusion, the phylogenetic analysis showed that the distribution of Brazilian VP1 sequences agrees with the ethnic composition of the country, indicating that VP1 can be successfully used for MCPyV phylogenetic studies. Finally, the structural analysis suggests that some mutations could have impact on the protein folding, membrane binding or antibody escape, and therefore they should be further studied.

Herpes simplex virus ophthalmic disease induced using two different methods of mice inoculation

Two different procedures for inoculation of HSV on corneas of BALB/c mice were evaluated. The first was by the use of HSV suspensions directly on the corneas and the other was after corneal scarification. Animals by this later method presented greater morbidity and mortality than those of first group, suggesting that inoculation of HSV without scarification of the cornea should be the method of choice for the study of HSV ophthalmic infection. This model showed also be an efficient experimental system to testing antiviral drugs.