Kathleen Victoir

How to succeed in parasitic life without sex? Asking Leishmania.

Eukaryotes use sexual recombination to achieve innovation and adaptation to a changing environment, a mechanism that is exceptional in Leishmania. It is postulated that asexual mechanisms contribute efficiently to parasite fitness and that sexual recombination would not be necessary for the production of a large repertoire of genotypes. The model discussed in this review used a major Leishmania glycoprotein, gp63, which is involved in host-parasite relationships. Mitotic recombination, which occurs between and within tandem repeats, amplifies genes and generates genotypic diversity. The resulting variation in the protein sequence is concentrated in surface domains, in regions spanning T-cell epitopes and B-cell epitopes and might allow immune escape.

Gp63 gene polymorphism and population structure of Leishmania donovani complex: influence of the host selection pressure?

The gp63 encoding genes were characterized by PCR-RFLP in 35 isolates representative of the Leishmania donovani complex (L. infantum, L. donovani, L. archibaldi and L. chagasi), with special attention to Mediterranean L. infantum from different geographical origins, and in separate groups from Old World Leishmania (L. major, L. tropica and L. aethiopica). The aim was to evaluate how the possible selective pressure by the host on these important surface proteins would influence structuring of our sample. Comparison was carried out with the structure obtained (i) from reported isoenzyme data, characters supposed to vary neutrally, and (ii) from PCR-RFLP analysis of gp63 inter-genic regions, containing nontranslated spacers and regulatory genes. Polymorphism within the gp63-encoding region, was much higher than in gp63 inter-genic regions. In the gp63 intra-genic dendrogram, the 4 species of L. donovani complex were discriminated and quite distinct from outgroups. Within L. infantum, geographical structuring was observed and did not overlap with the structure built-up from isoenzymes and inter-genic data. These results support the idea of a strong host-selection on gp63, at vector level but most of all at vertebrate (human or dog) immunological level. Furthermore, they illustrate how the nature of genetic characters may influence the perception of population structuring.

Research priorities for neglected infectious diseases in Latin America and the Caribbean Region

Global priorities for research in neglected infectious diseases (NIDs) can be assessed in different ways, but it is important to realize that regional priorities may significantly differ one from another. The region of Latin America and the Caribbean (LAC) is - along with Africa and Asia - more affected by NIDs than other regions of the world. Some of the Latin American NIDs are common to other continents, while others are very specific or disproportionately affect the Latin American region [1]-[3] (Table 1). Because of its huge ecological diversity, ongoing environmental changes, and massive migrations, LAC is also a catalyst for the (re-)emergence and spreading of NIDs, both inside and outside the subcontinent. Following a colloquium on NIDs in LAC held in Lima, Peru, between 12 and 14 November 2009, a thematic workshop was organized with the support of the European Commission (EC). It involved 29 scientists (16 from the Americas, two from the Democratic Republic of Congo and India, respectively, and nine from Europe) working on different NIDs and representing several research areas from basic to applied. This report summarizes the consensus comments of the expert group after oral and written consultation. It is envisaged that this document should stimulate a debate within the scientific community and serve as a recommendation for future actions by international or regional funding agencies in the area of NIDs in LAC.

Sentinel surveillance for influenza and other respiratory viruses in Côte d’Ivoire, 2003–2010

Background  Many countries in Africa have lacked sentinel surveillance systems for influenza and are under‐represented in data used for global vaccine strain selection.

First introduction of pandemic influenza A/H1N1 and detection of respiratory viruses in pediatric patients in Central African Republic

BackgroundAcute viral respiratory illnesses in children in sub-Saharan Africa have received relatively little attention, although they are much more frequent causes of morbidity and mortality than in developed countries. Active surveillance is essential to identify the causative agents and to improve clinical management, especially in the context of possible circulation of pandemic viruses.FindingsA prospective study was conducted in the Central African Republic (CAR) between January and December 2010 among infants and children aged 0–15 years attending sentinel sites for influenza-like illness or acute respiratory illness. Nasopharyngeal swabs were collected, and one-step real-time and multiplex reverse transcription-polymerase chain reaction were used to detect respiratory viruses. Respiratory viruses were detected in 49 of the 329 (14.9%) nasopharyngeal samples: 29 (8.8%) contained influenza viruses (5 (1.5%) had pandemic influenza A/H1N1 virus and 24 (7.3%) had influenza B viruses), 11 (3.3%) contained parainfluenza viruses types 1 and 3 and 9 (2.7%) contained human respiratory syncytial virus. Most cases were detected during the rainy season in the CAR. Analysis of the amplicon sequences confirmed the identity of each detected virus.ConclusionsThe influenza surveillance system in the CAR has provided valuable data on the seasonality of influenza and the circulation of other respiratory viruses. Our network could therefore play a valuable role in the prevention and control of influenza epidemics in the CAR.

Surveillance of Arthropod-Borne Viruses and Their Vectors in the Mediterranean and Black Sea Regions Within the MediLabSecure Network

Purpose of ReviewArboviruses, viruses transmitted by arthropods such as mosquitoes, ticks, sandflies, and fleas are a significant threat to public health because of their epidemic and zoonotic potential. The geographical distribution of mosquito-borne diseases such as West Nile (WN), Rift Valley fever (RVF), Dengue, Chikungunya, and Zika has expanded over the last decades. Countries of the Mediterranean and Black Sea regions are not spared. Outbreaks of WN are repeatedly reported in the Mediterranean basin. Human cases of RVF were reported at the southern borders of the Maghreb region. For this reason, establishing the basis for the research to understand the potential for the future emergence of these and other arboviruses and their expansion into new geographic areas became a public health priority. In this context, the European network “MediLabSecure” gathering laboratories in 19 non-EU countries from the Mediterranean and Black Sea regions seeks to improve the surveillance (of animals, humans, and vectors) by reinforcing capacity building and harmonizing national surveillance systems to address this important human and veterinary health issue. The aim of this review is to give an exhaustive overview of arboviruses and their vectors in the region.Recent FindingsThe data presented underline the importance of surveillance in the implementation of more adapted control strategies to combat vector-borne diseases. Partner laboratories within the MediLabSecure network present a wide range of infrastructures and have benefited from different training programs.SummaryAlthough reporting of arboviral presence is not carried out in a systematic manner, the expansion of the area where arboviruses are present cannot be disputed. This reinforces the need for increasing surveillance capacity building in this region to prevent future emergences.

Risk of Zika virus transmission in the Euro-Mediterranean area and the added value of building preparedness to arboviral threats from a One Health perspective

In the alarming context of risk of Zika virus (ZIKV) transmission in the Euro-Mediterranean area, there is a need to examine whether capacities to detect, diagnose and notify ZIKV infections in the region are in place and whether ongoing capacity-building initiatives are filling existing gaps.The MediLabSecure network, created in 2014, comprises 55 laboratories of virology and medical entomology and 19 public health institutions in 19 countries in the Balkans, North-Africa, the Middle-East and the Black Sea regions. It aims to set up awareness, risk assessment, monitoring and control of emerging and re-emerging vector-borne viruses. We here examine the actions and strategies that MediLabSecure has been implementing and how they will contribute to the prevention and control of the ZIKV threat in the Euro-Mediterranean area.Capacity-building for arbovirus diagnostics is a major objective of the project and follows a methodological rather than disease-driven approach. This enables the implementation of laboratory trainings on techniques that are common to several arboviruses, including ZIKV, and putting into action appropriate diagnostic tools in the target region.Moreover, by its One Health approach and the interaction of its four sub-networks in human virology, animal virology, medical entomology and public health, MediLabSecure is fostering intersectoral collaboration, expertise and sharing of information. The resulting exchanges (methodological, communication and operational) across disciplines and across countries, dedicated research on intersectoral collaboration and increasing diagnostic capacities are providing new paths and tools to public health professionals to face emerging viral threats such as a ZIKV epidemic in the Euro-Mediterranean region.

Les leishmanioses vues au travers du réseau international des Instituts Pasteur

Protozoan parasites of the genus Leishmania generate severe human diseases termed leishmaniases. Due to their frequency and the severity of certain clinical forms, these diseases represent a major public health problem and limit the economic growth in various developing countries. The presence of Pasteur Institutes in countries with endemic leishmaniasis has provided important incentives to develop a strong public health agenda in the Pasteur scientific community with respect to this important disease. A concerted effort is now coordinated through the recently created LeishRIIP platform (www.leishriip.org), which aims to identify synergies and complementary expertise between the eleven members of the international network of Pasteur Institutes working on various aspects of the disease including epidemiology, diagnosis, chemotherapy and vaccination.

Genetic and antigenic characterization of influenza A(H3N2) in Cameroon during the 2014-2016 influenza seasons

The first outbreak of influenza A(H3N2) occurred in 1968 and caused the third flu pandemic of the 20th century. It has affected multiple countries over time. The best strategy to reduce the burden of influenza is through vaccination whose efficacy varies with respect to the circulating strains. This study was performed to better understand the molecular evolution of influenza A(H3N2) and assess vaccine efficacy in Cameroon. Complete sequences of three gene segments were obtained from 2014 to 2016 influenza seasons in Cameroon. Hemagglutinin (HA), Neuraminidase (NA) and matrix (M) genes of 35 A(H3N2) virus strains were amplified and sequenced. Predicted vaccine efficacy was measured using the Pepitope model. Phylogenetic analysis of the HA gene showed that all Cameroonian strains had evolved away from the 3C.1-A/Texas/50/2012-like clade. Globally, 2014 virus strains clustered with the 2015–2016 vaccine strain, 3C.3a-A/Switzerland/9715293/2013, whereas 2015 and 2016 virus strains clustered with the 2016–2017 vaccine strain, 3C.2a-A/HongKong/4801/2014. In order to determine the genotypic drug susceptibility to neuraminidase inhibitors and amantadine, the NA and M2 protein coding sequences were analyzed. There was no strain with characteristic mutation for resistance to neuraminidase inhibitors, per contra; all strains possessed the substitution S31N, peculiar of resistance to adamantanes. There was drift in influenza A(H3N2) dominant epitopes B (2014 and 2015) to epitopes A (2016) with a theoretical efficiency in vaccine ranging from low to moderate. The presence of several antigenic site mutations among H3N2 virus strains between 2014–2016 influenza seasons in Cameroon confirms the progressing evolution of circulating H3N2 strains.

Strengthening Preparedness for Arbovirus Infections in Mediterranean and Black Sea Countries: A Conceptual Framework to Assess Integrated Surveillance in the Context of the One Health Strategy

In the context of One Health, there is presently an effort to integrate surveillance of human, animal, entomological, and environmental sectors. This aims to strengthen the prevention of, and preparedness against, arbovirus infections, also in the light of environmental and climate changes that could increase the risk of transmission. However, criteria to define integrated surveillance, and to compare different systems, still need to be identified and tested. We conducted a scoping review to identify and examine surveillance systems for West Nile virus (WNV), chikungunya virus (CHKV), dengue virus (DENV), and Rift Valley fever virus (RVFV), which involve human, animal, entomological, and environmental sectors. We analyzed findings using a conceptual framework we developed for this purpose. The review highlights that the criteria proposed in the conceptual framework to describe integrated surveillance are consistently reported in the context of studies and programs related to integrated surveillance of the selected arboviral diseases. These criteria can facilitate the identification and description of operationalized One Health surveillance.