Fátima Bacellar

Rats of the genus Rattus are reservoir hosts for pathogenic Bartonella species: an Old World origin for a New World disease?

Bartonella species were isolated from the blood of 63 of 325 Rattus norvegicus and 11 of 92 Rattus rattus from 13 sites in the United States and Portugal. Infection in both Rattus species ranged from 0% (e.g., 0/87) to approximately 60% (e.g., 35/62). A 337-bp fragment of the citrate synthase (gltA) gene amplified by polymerase chain reaction was sequenced from all 74 isolates. Isolates from R. norvegicus were most similar to Bartonella elizabethae, isolated previously from a patient with endocarditis (93%-100% sequence similarity), followed by Bartonella grahamii and other Bartonella species isolated from Old World rodents (Clethrionomys species, Mus musculus, and Rattus species). These data suggest that Rattus species are a reservoir host for pathogenic Bartonella species and are consistent with a hypothesized Old World origin for Bartonella species recovered from Rattus species introduced into the Americas.

Mediterranean Spotted Fever in Portugal

Abstract: Mediterranean spotted fever (MSF) is the most important tick‐borne disease in Portugal. It is a notifiable disease and during 1989–2000 the annual incidence rate in Portugal was 9.8/105 inhabitants. Although recognized as a benign acute disease and treated mainly with ambulatory procedures, some cases are severe and fatalities have increased in the last few years. In 1997, MSF mortality became more evident in Beja, a Portuguese southern district, with a case fatality rate of 32.3% in hospitalized patients. Analysis of 55 variables regarding epidemiologic, clinical, laboratory, and therapeutic data of fatal and nonfatal MSF cases were compared to identify risk factors in 105 patients hospitalized in Beja District Hospital, between 1994 and 1998. It was statistically significant that the patients dying in 1997 were younger than those in other years. The risk of dying is statistically significant in those who presented with diabetes, vomiting, dehydration, and uremia. The interval between the onset of symptoms to administration of anti‐rickettsial therapy was the same for all patients. Therapy delay, reported by some authors to be associated with mortality of MSF, was not a risk factor in our study. The patients who died in 1997 died faster than those in other years. The variables studied could not explain the higher mortality rates observed in our study. Although one may speculate that the pathogenic strain of Israeli tick typhus, isolated in 1997, could be responsible for this increase of fatality rate, inherited patient factors might also be strongly associated with mortality.

Rickettsia sibirica isolation from a patient and detection in ticks, Portugal.

First R. sibirica–related strain is detected.

The hard-tick fauna of mainland Portugal (Acari: Ixodidae): an update on geographical distribution and known associations with hosts and pathogens

This work is an updated revision of the available information on Portuguese ixodid tick species. It includes data on tick biology, ecology, taxonomy and host/pathogen-associations. The current list of Portuguese ixodid ticks comprises twenty species: Dermacentor marginatus (Sulzer, 1776), Dermacentor reticulatus (Fabricius, 1794), Haemaphysalis hispanica Gil Collado, 1938, Haemaphysalis inermis Birula, 1895, Haemaphysalis punctata Canestrini & Fanzago, 1878, Hyalomma lusitanicum Koch, 1844, Hyalomma marginatum Koch, 1844, Ixodes acuminatus Neumann, 1901, Ixodes bivari Dias, 1990, Ixodes canisuga Johnston, 1849, Ixodes frontalis (Panzer, 1798), Ixodes hexagonus Leach, 1815, Ixodes ricinus (Linnaeus, 1758), Ixodes simplex Neumann, 1906, Ixodes ventalloi Gil Collado, 1936, Ixodes vespertilionis Koch, 1844, Rhipicephalus (Boophilus) annulatus (Say, 1821), Rhipicephalus bursa Canestrini & Fanzago, 1878, Rhipicephalus pusillus Gil Collado, 1938, and Rhipicephalus sanguineus (Latreille, 1806).

Ticks Parasitizing Wild Birds in Portugal: Detection of Rickettsia aeschlimannii, R. helvetica and R. massiliae

From January 2002 to December 2004, 152 ticks were collected from 40 wild birds recovered in Santo André Natural Reserve and Monsanto Forestal Park, Portugal mainland. Five ticks species were identified from 22 species of birds, and new host record were provided for some species. In addition, 32 (21%) ticks were screened by PCR to detect infections with agents belonging to order Rickettsiales: Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Rickettsia spp. PCR amplicons were obtained in 5 (15.6%) tick samples. Rickettsia DNA exhibiting gltA sequences similar to those of Rickettsia aeschilimannii, R. helvetica and R. massiliae were identified in Hyalomma marginatum, Ixodes ventalloi and in Rhipicephalus turanicus, respectively. This is the first report of rickettsiae infections in ticks collected from wild birds in Portugal. Giving the results presented above wild birds play an important role in the maintenance and dissemination of several tick species and associated rickettsiae.

Report of Eight Cases of Fatal and Severe Mediterranean Spotted Fever in Portugal

Abstract: Mediterranean spotted fever (MSF), endemically present, is associated with a low mortality and morbidity in Portugal. Etiological agents are Malish and Israeli tick typhus strains of Rickettsia conorii. In the last few years severe forms of MSF have emerged, with patients presenting atypical symptoms, major neurological manifestations, and multiorgan involvement, who have required intensive care facilities. Advanced age, underlying chronic disease, and delay of appropriate treatment are bad prognostic factors. In the acute phase of diagnosis, serological studies are delayed, inconclusive, and often unhelpful. A definitive diagnosis can only be made using isolation or molecular biology which can establish and clearly identify agents. Using evidence‐based case reports, clinical and laboratory data were evaluated from patients with severe or fatal MSF observed in Garcia da Orta Hospital‐Almada. Of the eight reference cases, four died, three in an acute fulminant stage. Of the survivors, four presented atypical involvement: ocular inoculation, massive gastric hemorrhage, acute respiratory disease (ARDS), and necrotizing vasculitis. Diagnosis by isolation of the agent was made in two cases, by immunohistochemistry in three, and by the indirect fluorescent antibody test (IFA) in three others. Israeli tick typhus and Malish R. conorii strains were isolated once each in fatal cases. In early stages, diagnosis continues to be clinical and patients should start appropriate therapy without delay if clinical suspicion of rickettsiosis arises to prevent poor outcome. Patients ranged in age from 39 to 71 years (mean 60), APACHE II ranged from 15 to 38 points and TISS 28 was between 24 and 46 points. In reported cases severity of disease was not obviously related to the usual comorbidities. Accelerated clinical course may not suggest classical MSF. Another relevant factor was prior prescription of an inappropriate antibiotic that contributed to misleading clinical features. The reported complications and atypical manifestations illustrate well the diversity of this disease.

Israeli spotted fever rickettsia (Rickettsia conorii complex) associated with human disease in Portugal.

other is a small clinical and epidemiologic study of hospitalized children <2 years of age in Santiago de Compostela (8). Data from both studies are consistent with our results. Rotavirus gastroenteritis is a common cause of hospitalization and produces a heavy load on the health-care system in our region. After years of research, vaccines that effectively prevent rotavirus infections in humans have been developed (9,10). These data should be considered in evaluating the potential benefits of introducing rotavirus vaccine in our region and monitoring its effectiveness.

Human ehrlichioses in Brazil : first suspect cases.

Brazilian spotted fever (BSF) rickettsiosis is the most common and recognized of the human rickettsioses in Brazil. It is difficult to establish the diagnosis of human rickettsiosis infection by routine microbiologic methods, creating a false idea that Rickettsia and Ehrlichia infections are rare and without importance. New tick-borne diseases, like human granulocytic anaplasmosis (HGA) and human monocytic ehrlichiosis (HME), have been described in many countries. These diseases can present symptoms similar to rickettsioses of the spotted fever group, and they are transmitted by ixodid ticks. The first two suspected cases of human ehrlichiosis in Brazil were first considered to be cases of BSF. The differential diagnosis was made at the Minas Gerais Rickettsiosis Public Health Laboratory. The clinical and laboratory findings, with positive serology for the HME agent, indicated suspected cases of human ehrlichioses in Brazil.

Intralesional Expression of mRNA of Interferon-γ, Tumor Necrosis Factor-α, Interleukin-10, Nitric Oxide Synthase, Indoleamine-2,3-Dioxygenase, and RANTES Is a Major Immune Effector in Mediterranean Spotted Fever Rickettsiosis

BACKGROUND The mechanisms of immunity to Rickettsia conorii that have been elucidated in mouse models have not been evaluated in human tissues. METHODS In this study, quantitative real-time polymerase chain reaction was used to determine the levels of expression of inflammatory and immune mediators in skin-biopsy samples collected from 23 untreated patients with Mediterranean spotted fever (MSF). RESULTS In all 23 patients, the levels of intralesional expression of mRNA of tumor necrosis factor (TNF)- alpha , interferon (IFN)- gamma , interleukin (IL)-10, RANTES, and indoleamine-2,3-dioxygenase (IDO), an enzyme involved in limiting rickettsial growth by tryptophan degradation, were higher than those in control subjects; 6 of the 23 patients had high levels of inducible nitric oxide synthase (iNOS), a source of microbicidal nitric oxide. Positive correlations between TNF- alpha , IFN- gamma , iNOS, IDO, and mild/moderate MSF suggest that type 1 polarization plays a protective role. Significantly higher levels of intralesional expression of IL-10 mRNA were inversely correlated with levels of intralesional expression of IFN- gamma mRNA and TNF- alpha mRNA. The mRNA-expression level of the chemokine RANTES was significantly higher in patients with severe MSF. CONCLUSION Mild/moderate MSF is associated with a strong and balanced intralesional proinflammatory and anti-inflammatory response, with a dominant type 1 immunity, whereas severe MSF is associated with increased expression of chemokine mRNA. Whether these factors are simply correlates of mild and severe MSF or contribute to antirickettsial immunity and pathogenesis remains to be determined.

Ultrastructural study of the infection process of Rickettsia conorii in the salivary glands of the vector tick Rhipicephalus sanguineus.

This work was designed to study the infection process of Rickettsia conorii in the salivary glands of experimentally infected Rhipicephalus sanguineus ticks. One hundred six uninfected engorged nymphs were intracelomically inoculated with approximately 2 x 10(3) plaque-forming units of a rickettsial suspension. After the molt, unfed and fed adults were dissected, and the salivary glands were extracted and processed for transmission electron microscopy observation. Three different uninfected control groups were used for (1) evaluating the impact of the inoculation procedure, (2) establishing the feeding period of infected ticks, and (3) ultrastructural characterization of the salivary glands. Overall, 75.5% (80 of 106) of the nymphs inoculated with rickettsiae died during the molt or soon after hatching into adult instars; 50% (12 of 24) of the remaining infected adults showed severe malformations compromising their viability. In apparently healthy specimens, time of engorgement was longer. The contrast with the negative control groups was statistically significant, suggesting that R. conorii exerts a strong negative effect on the vector ticks. The ultrastructural study showed that in the salivary glands of infected ticks, rickettsial growth occurs preferentially in central, peripheral, and interstitial acini cells.