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analysis of biological samples from these animal populations provides the first
definitive evidence of
A. phagocytophilum
active infection in Portuguese
vertebrates with detection of its DNA in one seropositive horse from mainland
Portugal, where the
A. phagocytophilum
genotype found is closely related to
strains isolated from humans, suggesting the potential for HGA in Portugal. This
thesis further extends study to identification of another closely related
Anaplasma
species, and its potential for serological cross-reactions with
A.
phagocytophilum
, as evident with the detection of
A. platys
DNA in seropositive
dogs. These data also underscore the importance of veterinarians maintaining
vigilance for detection of not only granulocytic anaplasmosis but also canine
infectious cyclic thrombocytopenia as causes of tick-borne diseases in Portugal.
Both prospective and retrospective serological and molecular investigations of
human exposure to
A. phagocytophilum
were performed on samples received
at
CEVDI/INSA
for the laboratory diagnosis of patients with suspected tick-
borne diseases during 2000-2006. The results provide evidence for seropositive
Portuguese patients, including cases that fulfil serological criteria for HGA,
although active infections were not detected. Moreover some seropositive
patients had additional evidence of other tick-borne agents or related bacteria
infections, including Lyme borreliosis, Q fever and bartonellosis. Although
possibly false positive cross-reactions to shared antigens, these reactions
potentially could be the result of active dual infections, or past exposure to
several agents transmitted by
Ixodes
species. Overall, these results argue for
continued development of improved
A. phagocytophilum
diagnostics, especially
direct detection techniques, and integrated analysis of diagnostic tests for
patients with suspected
Ixodes
-borne disease.
Although many aspects introduced and explored here will require expanded and
more detailed investigations, this thesis contributes positively to a fundamental
understanding of the extent to which
A. phagocytophilum
occurs in Portugal and
its potential as a disease agent. It is hoped that these beginning studies will
help to delineate new lines of research that more fully address granulocytic
anaplasmosis and other emerging
Ixodes
-borne diseases.
ALVES, Maria Margarida (2006) Caracterização epidemiológica da
criptosporidiose em Portugal, por estudo molecular de isolados
de
Cryptosporidium
spp de humanos e de animais, Dissertação de
Doutoramento no ramo de Ciências Biomédicas, especialidade de
Parasitologia. IHMT. Lisboa.
RESUMO
Cryptosporidium
spp. é um protozoário ubíquo causador de patologia
gastrintestinal em humanos e animais. A infecção ocorre por ingestão de
oocistos, após contacto directo com pessoas – transmissão antroponótica – ou
outros animais infectados – transmissão zoonótica – podendo, ainda, ocorrer,
indirectamente, através da água ou de alimentos contaminados. A importância
relativa dos diferentes modos de transmissão, não se encontra, ainda,
esclarecida.
A criptosporidiose humana está associada, sobretudo, à infecção por
C.
hominis
e por
C. parvum
, embora se encontrem descritos, também, casos de