Lyme disease in Portugal

Topics with information and discussion about published studies related to Lyme disease and other tick-borne diseases.
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Yvonne
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Lyme disease in Portugal

Post by Yvonne » Mon 17 Sep 2007 10:48

Laboratory diagnosis of Lyme borreliosis at the Portuguese National Institute of Health (1990-2004)

Lyme borreliosis is considered to be an emerging infection in some regions of the world, including Portugal. The first Portuguese human case of Lyme borreliosis was identified in 1989. Since 1999, this disease is considered a notifiable disease (DDO) in Portugal, but only a few cases are reported each year, which does not allow consistent analysis of risk factors and the impact on public health. In this study the authors analyse the data available at the Centre for Vectors and Infectious Diseases Research (CEVDI) laboratory, at the Instituto Nacional de Saúde Dr. Ricardo Jorge (National Institute of Health, INSA) during the past 15 years (1990-2004) and evaluate them against the registry of national reported cases (1999-2004). Serological tests were the basis for laboratory diagnosis. Data on year of diagnosis, sex, age, geographical origin and clinical signs are available for 628 well documented Portuguese positive cases. The number of cases per year varied between 2 and 78, with the highest number of cases reported in 1997. Of the positive cases, 53.5% were female and the age group most affected was 35-44 years old. Neuroborreliosis was the most common clinical manifestation (37.3%). Human cases were detected in 17 of the 20 regions of Portugal, and the highest number of laboratory confirmed cases were from the Lisbon district. The comparison of the number of notified cases and the number of positive cases confirmed by our laboratory show that Lyme borreliosis is clearly an underreported disease. Due to the scattered distribution of the positive cases and the low prevalence of the tick species Ixodes ricinus, the most effective prevention measure for Lyme borreliosis in Portugal is education of the risk groups on how to prevent tick bites.


Introduction
Lyme borreliosis has been reported throughout Europe where it is the most common tickborne infection, as it is in the United States [1].
Clinically, it shows up as a multisystemic disease, presenting dermatological, rheumatic, neurological and cardiac manifestations.
The first reported human case of Lyme disease in Portugal was identified in 1989 [2]. Diagnosis is preformed by the Centre for Vectors and Infectious Diseases Research (CEVDI) at the Instituto Nacional de Saúde Dr. Ricardo Jorge (National Institute of Health, INSA), using several techniques including culture, PCR, and antibody detection. The first strains of Borrelia burgdorferi sensu lato were isolated from ticks captured in the south of Portugal [3] and the study showed that they belong to a new species, B. lusitaniae [4]. Subsequent studies confirm the presence of several B. burgdorferi s.l. species (B. lusitaniae, B. afzelii, B. garinii and B. valaisiana) in ticks and the infection prevalence could vary between: studies have found prevalences of 11.9% (n= 234, collected in several regions), 11.8% (n= 2806, Mafra region), 34.7% (n=206, Grandola region); and 31.2% (n=285, the island of Madeira) [5, 6, 7, 8]. In all the studies made so far, B. lusitaniae is the most prevalent borrelia species. Recently, a strain of this species was isolated from a human sample, indicating that it could cause disease in humans [9]. Other species of borrelia, B. garinii, B. afzelii B. burgdorferi sensu stricto and B. valaisiana have already been detected in mainland Portugal and/or the island of Madeira [5, 10]. Since 1999, Lyme borreliosis has been a mandatorily notifiable disease in Portugal, but only a few cases are reported each year, which does not allow consistent analysis of risk factors and the impact on public health. The aim of this study was to contribute to a more precise evaluation of the epidemiological situation of Lyme borreliosis in Portugal, analysing the data available at the CEVDI’s laboratory concerning the serological diagnosis of this disease and data available on the statutory notifiable disease register.

Results:

Among 12 535 biological samples taken for analysis from patients with clinical suspicion of Lyme borreliosis, 628 (5%) tested positive using the EUCALB diagnostic criteria.
In patients with neurological symptoms, CSF was sometimes sent for analysis (21%). Data is available describing the 628 Portuguese patients, 129 of whom tested positive for both CSF and sera. The remaining 499 patients were diagnosed based in the result of sera analysis, with the observation of seroconversion. The number of cases per year varied between 2 and 78, with the highest number of cases in 1997 [FIGURE 1].

http://www.eurosurveillance.org/em/v11n10/1110-223.asp
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Yvonne
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Joined: Fri 27 Jul 2007 16:02

Re: Lyme disease in Portugal

Post by Yvonne » Sun 1 Jun 2008 11:04

Vector Borne Zoonotic Dis. 2008 May 2. [Epub ahead of print] Links

Detection of Borrelia lusitaniae, Rickettsia sp. IRS3, Rickettsia monacensis, and Anaplasma phagocytophilum in Ixodes ricinus Collected in Madeira Island, Portugal.

De Carvalho IL, Milhano N, Santos AS, Almeida V, Barros SC, De Sousa R, Núncio MS.
Centro de Estudos de Vectores e Doenças Infecciosas, Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisboa, Portugal.

A total of 300 Ixodes ricinus ticks were tested by polymerase chain reaction (PCR) for the presence of Borrelia spp., Rickettsia spp., and Anaplasma phagocytophilum. Sequence analysis demonstrated 8 (2.7%) ticks infected with B. lusitaniae, 60 (20%) with Rickettsia spp., and 1 (0.3%) with A. phagocytophilum. Seven (2.3%) ticks were coinfected with B. lusitaniae and Rickettsia spp., 2 (0.6%) with R. monacensis, and 5 (1.7%) with Rickettsia sp. IRS3. The results of this study suggest simultaneous transmission of multiple tick-borne agents on Madeira Island, Portugal.

PMID: 18454598
Listen to all,
plucking a feather from every passing goose,
but follow no one absolutely

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