Sérgio Ramalho de Sousa

Prof. Dr. Sérgio Ramalho de Sousa

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Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 June 2015 in Journal of Feline Medicine and Surgery
Verified
Journal Article
Closed access
CSCarla Soares
Carla Soares
SDSofia Duarte
Sofia Duarte
SSSérgio Ramalho de Sousa
Sérgio Ramalho de Sousa
According to the World Health Organization (WHO), endemic areas of leishmaniosis have spread and the number of reported cases has increased. Europe is one of the continents with greatest risk of the re-emergence of this zoonosis. The significance of the cat as a reservoir of Leishmania species and not simply an accidental host seems to be gaining ground, mainly because: (i) cats can present increased seropositivity between serological analyses, but the pattern of seropositivity is not consistent between cats; (ii) cats can be infected for some months and thus are available for sandflies; and (iii) cats transmit the Leishmania species agent in a competent form. Furthermore, cats have behavioural characteristics that contribute to infection by Leishmania infantum and, as such, feline leishmaniosis (FeL) has been reported worldwide. When clinical signs of FeL are present, they are non-specific and frequently occur in other feline diseases. If they go undiagnosed, they can contribute to an underestimation of the actual occurrence of the disease in cats. The low seroprevalence titres, along with the commonly asymptomatic infection in cats, can further contribute to the underestimation of FeL occurrence. This work aims to raise awareness about FeL among veterinarians by providing a review of the current status of FeL infection caused by L infantum worldwide, the major clinicopathological features of infection, along with recent developments on FeL diagnosis, treatment and prevention.

10 May 2016 in Parasites & Vectors
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Journal Article
Open access
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Luís CardosoLuís Cardoso
Luís Cardoso
AOAna Cristina Oliveira
Ana Cristina Oliveira
SGSara Granada
Sara Granada
YNYaarit Nachum-Biala
Yaarit Nachum-Biala
MGMatan Gilad
Matan Gilad
Gad BanethGad Baneth
Gad Baneth
No molecular data have been available on tick-borne pathogens that infect dogs from Angola. The occurrence of agents from the genera Anaplasma, Babesia, Ehrlichia and Hepatozoon was assessed in 103 domestic dogs from Luanda, by means of the polymerase chain reaction (PCR) and DNA sequence analysis. Forty-six dogs (44.7 %) were positive for at least one pathogen. Twenty-one animals (20.4 %) were found infected with Anaplasma platys, 18 (17.5 %) with Hepatozoon canis, six (5.8 %) with Ehrlichia canis, six (5.8 %) with Babesia vogeli, one (1.0 %) with Babesia gibsoni and one (1.0 %) with an unnamed Babesia sp. The molecular frequency of single infections taken together was 37.9 % and that of co-infections with several combinations of two pathogens accounted for 6.8 % of the animals. This is the first report of A. platys, B. vogeli, B. gibsoni, E. canis and H. canis infections diagnosed by PCR in domestic dogs from Angola. The present study provides evidence that dogs in Luanda are widely exposed to, and at risk of becoming infected with, tick-borne pathogens. Further investigation is needed, including a larger number of animals, canine populations from other cities and provinces of the country, as well as potential vector ticks, aiming at better characterizing and controlling canine vector-borne diseases in Angola.

25 November 2022 in Biology
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Journal Article
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SASofia Ferreira Anastácio
Sofia Ferreira Anastácio
SSSérgio Ramalho de Sousa
Sérgio Ramalho de Sousa
Maria José SaavedraMaria José Saavedra
Maria José Saavedra
Gabriela Jorge Da SilvaGabriela Jorge Da Silva
Gabriela Jorge Da Silva
Since its first description in the late 1930s, Q fever has raised many questions. Coxiella burnetii, the causative agent, is a zoonotic pathogen affecting a wide range of hosts. This airborne organism leads to an obligate, intracellular lifecycle, during which it multiplies in the mononuclear cells of the immune system and in the trophoblasts of the placenta in pregnant females. Although some issues about C. burnetii and its pathogenesis in animals remain unclear, over the years, some experimental studies on Q fever have been conducted in goats given their excretion pattern. Goats play an important role in the epidemiology and economics of C. burnetii infections, also being the focus of several epidemiological studies. Additionally, variants of the agent implicated in human long-term disease have been found circulating in goats. The purpose of this review is to summarize the latest research on C. burnetii infection and the role played by goats in the transmission of the infection to humans.

1 September 2013 in Veterinary Parasitology
Verified
Journal Article
Closed access
CSCarla Soares
Carla Soares
SSSérgio Ramalho de Sousa
Sérgio Ramalho de Sousa
SASofia Ferreira Anastácio
Sofia Ferreira Anastácio
MMMaria Goreti Matias
Maria Goreti Matias
IMInês Marquês
Inês Marquês
Domenico OtrantoDomenico Otranto
Domenico Otranto

13 December 2022 in Pathogens
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Journal Article
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SASofia Ferreira Anastácio
Sofia Ferreira Anastácio
SASamuel Costa Anjos
Samuel Costa Anjos
SNSuzi Neves
Suzi Neves
TNTiago Neves
Tiago Neves
PEPedro Esteves
Pedro Esteves
HVHugo Vilhena
Hugo Vilhena
Dogs and cats are potential sources of infection for some zoonotic diseases such as Q fever, caused by Coxiella burnetii, a multiple host pathogen. Q fever outbreaks in dogs and cats have been related with parturition and abortion events, and ticks have a potential role in the transmission of this pathogen. This study aimed to screen for C. burnetii in dogs and cats, and in ticks collected from infested animals. An observational descriptive study was conducted in Portugal at two time points nine years apart, 2012 and 2021. Sera obtained from dogs and cats (total n = 294) were tested for C. burnetii antibodies using a commercial ELISA adapted for multi-species detection. C. burnetii DNA was screened by qPCR assay targeting IS1111 in uterine samples and in ticks. A decrease in the exposure to C. burnetii was observed in cats from 17.2% (95% CI: 5.8–35.8%) in 2012 to 0.0% in 2021, and in dogs from 12.6% (95% CI: 7.7–19.0%) in 2012 to 1.7% (95% CI: 0.3–9.1%) in 2021 (p < 0.05). Overall, and despite differences in the samples, rural habitat seems to favour the exposure to C. burnetii. The DNA of C. burnetii was not detected in ticks. The low seropositivity observed in 2021 and the absence of C. burnetii DNA in the tested samples, suggest that dogs and cats from Portugal are not often exposed to the pathogen. Nevertheless, the monitoring of C. burnetii infection in companion animals is an important tool to prevent human outbreaks, considering the zoonotic potential for owners and veterinarians contacting infected animals, mainly dogs and cats from rural areas which often come into contact with livestock.

17 April 2025 in Microbiology Research
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Journal Article
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Joana Ferrolho GibsonJoana Ferrolho Gibson
Joana Ferrolho Gibson
SASandra Isabel Da Conceição Antunes
Sandra Isabel Da Conceição Antunes
HVHugo Vilhena
Hugo Vilhena
SASofia Ferreira Anastácio
Sofia Ferreira Anastácio
SSSérgio Ramalho de Sousa
Sérgio Ramalho de Sousa
ADAna Gonçalves Domingos
Ana Gonçalves Domingos
Canine monocytic ehrlichiosis (CME) is a highly infectious disease with zoonotic potential. Ehrlichia canis, the causative agent, is primarily transmitted by Rhipicephalus sanguineus. Tick infestation and tick-borne diseases (TBDs) are serious human and veterinary health problems due to the lack of efficient control measures. This review aims to provide information about CME, detailing epidemiology, pathogenesis, clinical manifestations, and current strategies for diagnosis, treatment, and prevention. The review delves into the biology of R. sanguineus, exploring its lifecycle, habitat, and mechanisms of E. canis transmission. Ehrlichia canis infection follows a three-phase transition: acute, subclinical, and chronic, with distinct clinical signs, from mild to severe and even life-threatening in some cases, with the potential for asymptomatic long-term carriers acting as reservoirs. Pathogenesis involves complex interactions between the pathogen and host immune responses, influencing disease severity and progression. Additionally, the review highlights challenges in controlling CME due to the widespread distribution of R. sanguineus. Genetic diversity within R. sanguineus populations and their varying vector competence further complicate control efforts. The role of environmental changes in tick distribution aligns the control of CME within the One Health concept, integrating approaches to improve outcomes for humans, animals, and the environment. Preventive measures on tick control and potential vaccine development are also reviewed.