Microorganisms

Research

10 pages, 1259 KiB

Open AccessArticle

Detection of Specific Antibodies against Toscana Virus among Blood Donors in Northeastern Italy and Correlation with Sand Fly Abundance in 2014

by Silvia Morini, Mattia Calzolari, Giada Rossini, Nadia Pascarelli, Andrea Porcellini, Vanda Randi, Maria Carla Re, Alessandro Albieri, Paolo Bonilauri, Romeo Bellini, Nazli Ayhan, Remi Charrel and Stefania Varani

Microorganisms 2020, 8(2), 145; https://doi.org/10.3390/microorganisms8020145 - 21 Jan 2020

Cited by 4 | Viewed by 2684

Abstract

Toscana virus (TOSV) is a Phlebovirus transmitted by phlebotomine sand flies and is an important etiological agent of summer meningitis in the Mediterranean basin. Since TOSV infection is often asymptomatic, we evaluated the seroprevalence in blood donors (BDs) in the Bologna and Ferrara [...] Read more.

Toscana virus (TOSV) is a Phlebovirus transmitted by phlebotomine sand flies and is an important etiological agent of summer meningitis in the Mediterranean basin. Since TOSV infection is often asymptomatic, we evaluated the seroprevalence in blood donors (BDs) in the Bologna and Ferrara provinces (Northeastern Italy)—the areas with the highest and lowest numbers of TOSV neuroinvasive cases in the region, respectively. A total of 1208 serum samples from BDs were collected in April–June 2014 and evaluated for the presence of specific TOSV-IgG by ELISA. The IgG-reactive samples were confirmed by indirect immunofluorescence assay (IIF) and by microneutralization test (MN). Serum samples were defined as positive for anti-TOSV IgG when reactive by ELISA and by at least one second-level test; TOSV seroprevalence was 6.8% in the Bologna province, while no circulation of TOSV was detected in the Ferrara province. Sand fly abundance in 2014 was also estimated by a geographic information system using a generalized linear model applied to a series of explanatory variables. TOSV seroprevalence rate was strongly associated with the sand fly abundance index in each municipality, pointing out the strong association between sand fly abundance and human exposure to TOSV. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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16 pages, 1715 KiB

Open AccessArticle

Zika Virus Infection in Pregnancy: Advanced Diagnostic Approaches in Dengue-Naive and Dengue-Experienced Pregnant Women and Possible Implication for Cross-Reactivity and Cross-Protection

by Maurizio Zavattoni, Francesca Rovida, Elena Percivalle, Irene Cassaniti, Antonella Sarasini, Alessia Arossa, Beatrice Tassis, Lina Bollani, Giuseppina Lombardi, Simona Orcesi and Fausto Baldanti

Microorganisms 2020, 8(1), 56; https://doi.org/10.3390/microorganisms8010056 - 28 Dec 2019

Cited by 3 | Viewed by 3416

Abstract

Zika virus (ZIKV) infection has been linked to congenital defects in fetuses and infants, as exemplified by the microcephaly epidemic in Brazil. Given the overlapping presence of Dengue virus (DENV) in the majority of ZIKV epidemic regions, advanced diagnostic approaches need to be [...] Read more.

Zika virus (ZIKV) infection has been linked to congenital defects in fetuses and infants, as exemplified by the microcephaly epidemic in Brazil. Given the overlapping presence of Dengue virus (DENV) in the majority of ZIKV epidemic regions, advanced diagnostic approaches need to be evaluated to establish the role of pre-existing DENV immunity in ZIKV infection. From 2015 to 2017, five pregnant women with suspected ZIKV infection were investigated in Pavia, Italy. Among the five pregnant women, three were DENV–ZIKV immunologically cross-reactive, and two were DENV-naïve. Advanced diagnosis included the following: (i) NS1 blockade-of-binding (BOB) ELISA assay for ZIKV specific antibodies and (ii) ELISpot assay for the quantification of effector memory T cells for DENV and ZIKV. These novel assays allowed to distinguish between related flavivirus infections. The three DENV-experienced mothers did not transmit ZIKV to the fetus, while the two DENV-naive mothers transmitted ZIKV to the fetus. Pre-existing immunity in DENV experienced mothers might play a role in cross-protection. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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11 pages, 3611 KiB

Open AccessArticle

Isolation and Molecular Typing of Leishmania infantum from Phlebotomus perfiliewi in a Re-Emerging Focus of Leishmaniasis, Northeastern Italy

by Mattia Calzolari, Elena Carra, Gianluca Rugna, Paolo Bonilauri, Federica Bergamini, Romeo Bellini, Stefania Varani and Michele Dottori

Microorganisms 2019, 7(12), 644; https://doi.org/10.3390/microorganisms7120644 - 3 Dec 2019

Cited by 11 | Viewed by 3431

Abstract

Visceral leishmaniasis (VL) caused by Leishmania (L.) infantum is a public health threat in the Emilia-Romagna region, northeastern Italy, but its epidemiology has not been fully elucidated in this area. The objective of this study was to characterize Leishmania infection in sand flies [...] Read more.

Visceral leishmaniasis (VL) caused by Leishmania (L.) infantum is a public health threat in the Emilia-Romagna region, northeastern Italy, but its epidemiology has not been fully elucidated in this area. The objective of this study was to characterize Leishmania infection in sand flies collected in a re-emerging focus of VL in the Bologna province. During the summer of 2016, 6114 sand flies were collected, identified, and tested for Leishmania detection. Of the identified sand flies, 96.5% were Phlebotomus (P.) perfiliewi and 3.5% were P. perniciosus. Detected parasites were characterized by biomolecular methods (multilocus microsatellite typing and characterization of repetitive region on chromosome 31), and quantified by real-time PCR. The prevalence of Leishmania infection in individually-tested P. perfiliewi sand flies varied from 6% to 10% with an increasing trend during the season. Promastigotes of L. infantum were isolated by dissection in one P. perfiliewi female; the isolated strain (Lein-pw) were closely related to Leishmania parasites from VL cases in northeastern Italy, but differed from strains isolated in dogs from the same area. Our findings strongly support the vector status of P. perfiliewi for human VL in the study area. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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13 pages, 3225 KiB

Open AccessArticle

Multiple Lineages of Usutu Virus (Flaviviridae, Flavivirus) in Blackbirds (Turdus merula) and Mosquitoes (Culex pipiens, Cx. modestus) in the Czech Republic (2016–2019)

by Vaclav Hönig, Martin Palus, Tomas Kaspar, Marta Zemanova, Karolina Majerova, Lada Hofmannova, Petr Papezik, Silvie Sikutova, Frantisek Rettich, Zdenek Hubalek, Ivo Rudolf, Jan Votypka, David Modry and Daniel Ruzek

Microorganisms 2019, 7(11), 568; https://doi.org/10.3390/microorganisms7110568 - 16 Nov 2019

Cited by 28 | Viewed by 4386

Abstract

Usutu virus (USUV) is a flavivirus (Flaviviridae: Flavivirus) of an African origin transmitted among its natural hosts (diverse species of birds) by mosquitoes. The virus was introduced multiple times to Europe where it caused mortality of blackbirds (Turdus merula [...] Read more.

Usutu virus (USUV) is a flavivirus (Flaviviridae: Flavivirus) of an African origin transmitted among its natural hosts (diverse species of birds) by mosquitoes. The virus was introduced multiple times to Europe where it caused mortality of blackbirds (Turdus merula) and certain other susceptible species of birds. In this study, we report detection of USUV RNA in blackbirds, Culex pipiens and Cx. modestus mosquitoes in the Czech Republic, and isolation of 10 new Czech USUV strains from carcasses of blackbirds in cell culture. Multiple lineages (Europe 1, 2 and Africa 3) of USUV were found in blackbirds and mosquitoes in the southeastern part of the country. A single USUV lineage (Europe 3) was found in Prague and was likely associated with increased mortalities in the local blackbird population seen in this area in 2018. USUV genomic RNA (lineage Europe 2) was detected in a pool of Cx. pipiens mosquitoes from South Bohemia (southern part of the country), where no major mortality of birds has been reported so far, and no flavivirus RNA has been found in randomly sampled cadavers of blackbirds. The obtained data contributes to our knowledge about USUV genetic variability, distribution and spread in Central Europe. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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16 pages, 1925 KiB

Open AccessArticle

Inflammatory Immune Responses in Patients with Tick-Borne Encephalitis: Dynamics and Association with the Outcome of the Disease

by Petra Bogovič, Lara Lusa, Miša Korva, Stanka Lotrič-Furlan, Katarina Resman-Rus, Miša Pavletič, Tatjana Avšič-Županc, Klemen Strle and Franc Strle

Microorganisms 2019, 7(11), 514; https://doi.org/10.3390/microorganisms7110514 - 31 Oct 2019

Cited by 19 | Viewed by 3499

Abstract

Information on the association of inflammatory immune responses and disease outcome after tick-borne encephalitis (TBE) is limited. In the present study, we assessed the levels of 24 cytokines/chemokines associated with innate and adaptive immune responses in matched serum and cerebrospinal fluid (CSF) samples [...] Read more.

Information on the association of inflammatory immune responses and disease outcome after tick-borne encephalitis (TBE) is limited. In the present study, we assessed the levels of 24 cytokines/chemokines associated with innate and adaptive immune responses in matched serum and cerebrospinal fluid (CSF) samples of 81 patients at first visit, and in serum at follow-up time points. Serum levels of several cytokines/chemokines obtained during the meningoencephalitic phase of TBE differed compared to the levels at a follow-up visit 2 months later; several significant differences were also found in cytokine/chemokine levels in serum at 2 months compared to the last time point, 2–7 years after acute illness. Cytokines/chemokines levels in CSF or serum obtained at the time of acute illness or serum levels obtained 2 months after the onset of TBE did not have predictive value for an unfavorable outcome 2–7 years later. In contrast, serum levels of mediators associated with Th17 responses were lower in patients with unfavorable outcome whereas those associated with other adaptive or innate immune responses were higher at the last visit in those with an unfavorable outcome. These findings provide new insights into the immunopathogenesis of TBE and implicate inflammatory immune responses with post-encephalitic syndrome years after the initial infection. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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12 pages, 761 KiB

Open AccessArticle

A Dengue Vaccine: Will It be Accepted and Is It Feasible? Lessons from Barranquilla, Colombia, and Merida, Venezuela

by Elizabeth McMahon, Liliana Encinales, Carlos Navarro Encinales, Silvana Vielma, Nelly Pacheco, Lil Geraldine Avendaño Echavez, Sandra Acosta Rodríguez, Milena Calderon, Silvia Encinales Sanabria, Lorena Encinales Sanabria, Ericka Serrano Bernal, Andrés Gonzaléz Coba, Dennys Jiménez, Gary Simon and Aileen Y. Chang

Microorganisms 2019, 7(10), 458; https://doi.org/10.3390/microorganisms7100458 - 16 Oct 2019

Cited by 2 | Viewed by 3302

Abstract

With one vaccine on the market and others in clinical trials, policy makers in dengue endemic regions face the decision of whether to introduce a dengue vaccine in their communities. The World Health Organization (WHO) recommends that individualized assessments be conducted before any [...] Read more.

With one vaccine on the market and others in clinical trials, policy makers in dengue endemic regions face the decision of whether to introduce a dengue vaccine in their communities. The World Health Organization (WHO) recommends that individualized assessments be conducted before any vaccine introduction to evaluate disease burden and the strength of current vaccination programs. This study seeks to aid in that decision-making process by examining the acceptability and feasibility of dengue vaccine introduction in Barranquilla, Colombia, and Merida, Venezuela. Surveys were administered February–June of 2018 for three groups: patients (n = 351), health professionals (n = 197), and government officials (n = 26). In Barranquilla, most respondents reported dengue to be a moderate-severe problem, that a dengue vaccine would be useful in their communities, and that their current vaccination programs could handle the addition of a new vaccine. In Venezuela, respondents were less likely to view dengue as a major concern and listed multiple barriers to not just dengue vaccine introduction, but to providing current vaccines as well. Further work is needed in Colombia to more objectively assess the country’s readiness as a whole for a future dengue vaccine. As political and social unrest continues in Venezuela, however, future initiatives should focus on trust and capacity building. This study can serve as a framework for future assessments of the acceptability and feasibility of a dengue vaccine in both targeted areas and on larger scales. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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7 pages, 1230 KiB

Open AccessArticle

Phylogenetic Analysis of Lednice Orthobunyavirus

by Rebeka Lucijana Berčič, Krisztián Bányai, Daniel Růžek, Enikő Fehér, Marianna Domán, Vlasta Danielová, Tamás Bakonyi and Norbert Nowotny

Microorganisms 2019, 7(10), 447; https://doi.org/10.3390/microorganisms7100447 - 13 Oct 2019

Cited by 5 | Viewed by 2843

Abstract

Lednice virus (LEDV) has been detected in Culex modestus mosquitoes in several European countries within the last six decades. In this study, phylogenetic analyses of the complete genome segments confirm that LEDV belongs to the Turlock orthobunyavirus (Orthobunyavirus, Peribunyaviridae) species [...] Read more.

Lednice virus (LEDV) has been detected in Culex modestus mosquitoes in several European countries within the last six decades. In this study, phylogenetic analyses of the complete genome segments confirm that LEDV belongs to the Turlock orthobunyavirus (Orthobunyavirus, Peribunyaviridae) species and is closely related to Umbre, Turlock, and Kedah viruses. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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10 pages, 2173 KiB

Open AccessArticle

Emergence of a Novel Ehrlichia minasensis Strain, Harboring the Major Immunogenic Glycoprotein trp36 with Unique Tandem Repeat and C-Terminal Region Sequences, in Haemaphysalis hystricis Ticks Removed from Free-Ranging Sheep in Hainan Province, China

by Junjiao Li, Xinxin Liu, Jiaqi Mu, Xibing Yu, Yidong Fei, Jin Chang, Yuhai Bi, Yulong Zhou, Zhuang Ding and Renfu Yin

Microorganisms 2019, 7(9), 369; https://doi.org/10.3390/microorganisms7090369 - 19 Sep 2019

Cited by 20 | Viewed by 4522

Abstract

Ehrlichia minasensis, a recently described Ehrlichia species that is the most closely related to, but clearly distinct from, Ehrlichia canis, has been circulating in not only bovines, cervids, and dogs but also several tick species from Canada, Brazil, France, Pakistan, Ethiopia, and [...] Read more.

Ehrlichia minasensis, a recently described Ehrlichia species that is the most closely related to, but clearly distinct from, Ehrlichia canis, has been circulating in not only bovines, cervids, and dogs but also several tick species from Canada, Brazil, France, Pakistan, Ethiopia, and Israel. However, there are no reports of E. minasensis in China. The purpose of this study was to explore whether E. minasensis is present naturally in ticks in China. Through PCR targeting of the genus-conserved dsb gene, E. minasensis DNA was detected in Haemaphysalis hystricis ticks removed from free-ranging sheep in Hainan Province, South China in 2017. The partial sequence of the dsb, 16S rRNA, and groEL genes demonstrated that the Hainan strain shared 99% identity with the dsb gene of E. minasensis strain UFMG-EV (GenBank: JX629808), with the 16S rRNA of E. minasensis isolate E-2650 (MH500005) and with the groEL gene of E. minasensis strain UFMG-EV (JX629806), respectively. Moreover, sequence analysis of the major immunogenic tandem repeat protein (trp36) revealed that the Hainan strain harbored a unique tandem repeat sequence (APEAAPVSAPEAAPVSAPVS) and a C-terminal region that differed from those of other known E. minasensis strains. Additionally, phylogenetic analysis based on the entire amino acid sequence of trp36 revealed that the Hainan strain was closely related to a recently described E. minasensis strain from Brazil, of which the sister clade contained different strains of E. canis. The discovery of this novel Hainan strain in H. hystricis ticks represents the first known natural presence of E. minasensis in South China, highlighting the need for its constant surveillance. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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13 pages, 1888 KiB

Open AccessArticle

Vδ2 T-Cells Kill ZIKV-Infected Cells by NKG2D-Mediated Cytotoxicity

by Eleonora Cimini, Alessandra Sacchi, Sara De Minicis, Veronica Bordoni, Rita Casetti, Germana Grassi, Francesca Colavita, Concetta Castilletti, Maria Rosaria Capobianchi, Giuseppe Ippolito, Maria Giovanna Desimio, Margherita Doria and Chiara Agrati

Microorganisms 2019, 7(9), 350; https://doi.org/10.3390/microorganisms7090350 - 12 Sep 2019

Cited by 9 | Viewed by 3387

Abstract

An expansion of effector/activated Vδ2 T-cells was recently described in acute Zika virus (ZIKV)-infected patients, but their role in the protective immune response was not clarified. The aim of this study was to define the antiviral activity of Vδ2 T-cells against ZIKV-infected cells. [...] Read more.

An expansion of effector/activated Vδ2 T-cells was recently described in acute Zika virus (ZIKV)-infected patients, but their role in the protective immune response was not clarified. The aim of this study was to define the antiviral activity of Vδ2 T-cells against ZIKV-infected cells. The Vδ2 T-cells expansion and their cytotoxic activity against ZIKV-infected cells were tested in vitro and analyzed by RT-PCR and flow cytometry. We found that ZIKV infection was able to induce Vδ2 T-cells expansion and sensitized A549 cells to Vδ2-mediated killing. Indeed, expanded Vδ2 T-cells killed ZIKV-infected cells through degranulation and perforin release. Moreover, ZIKV infection was able to increase the expression on A549 cells of NKG2D ligands (NKG2DLs), namely MICA, MICB, and ULBP2, at both the mRNA and protein levels, suggesting the possible involvement of these molecules in the recognition by NKG2D-expressing Vδ2 T-cells. Indeed, the killing of ZIKV-infected cells by expanded Vδ2 T-cells was mediated by NKG2D/NKG2DL interaction as NKG2D neutralization abrogated Vδ2 cytotoxicity. Our data showed a strong antiviral activity of Vδ2 T-cells against ZIKV-infected cells, suggesting their involvement in the protective immune response. Other studies are necessary to investigate whether the lack of Vδ2 T-cells expansion in vivo may be associated with disease complications. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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8 pages, 255 KiB

Open AccessCommunication

Antibody Response to Toscana Virus and Sandfly Fever Sicilian Virus in Cats Naturally Exposed to Phlebotomine Sand Fly Bites in Portugal

by André Pereira, Nazli Ayhan, José Manuel Cristóvão, Hugo Vilhena, Ângela Martins, Patrícia Cachola, Joaquim Henriques, Mónica Coimbra, Ana Catarino, Tereza Lestinova, Tatiana Spitzova, Petr Volf, Lenea Campino, Remi Charrel and Carla Maia

Microorganisms 2019, 7(9), 339; https://doi.org/10.3390/microorganisms7090339 - 11 Sep 2019

Cited by 9 | Viewed by 2983

Abstract

Phlebotomine sand fly-borne pathogens such as Leishmania spp. and phleboviruses are emerging threats to humans and animals worldwide. The aim of this work was to evaluate the exposure of cats from Portugal to Toscana virus (TOSV) and Sandfly Fever Sicilian virus (SFSV) and [...] Read more.

Phlebotomine sand fly-borne pathogens such as Leishmania spp. and phleboviruses are emerging threats to humans and animals worldwide. The aim of this work was to evaluate the exposure of cats from Portugal to Toscana virus (TOSV) and Sandfly Fever Sicilian virus (SFSV) and assess the associated risk factors. The possible association between exposure to Phlebotomus perniciosus saliva with TOSV and SFSV was also investigated. Out of 369 cats tested, 18 (4.9%, n = 365) were seropositive for TOSV, and eight (2.2%, n = 367) were seropositive for SFSV. Multivariate logistic regression analysis showed that cats presenting clinical signs that were compatible with leishmaniosis and antibodies to TOSV had a significantly higher risk of being SFSV seropositive. The presence of antibodies to sand fly-borne viruses in cats indicate that these animals are frequently exposed to sand flies and transmitted pathogens. Data suggest that cats can be used to qualitatively monitor human exposure to TOSV and SFSV in endemic areas. The clinical impact of SFSV in cats’ health should be investigated. The identification of the sand fly species responsible for the circulation of TOSV and SFSV in nature and the evaluation of the vectorial competence of P. perniciosus to SFSV should also be addressed. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

14 pages, 2393 KiB

Open AccessArticle

Sex-Specific Asymmetrical Attack Rates in Combined Sexual-Vectorial Transmission Epidemics

by Ana Carolina W. G. de Barros, Kaline G. Santos, Eduardo Massad and Flávio Codeço Coelho

Microorganisms 2019, 7(4), 112; https://doi.org/10.3390/microorganisms7040112 - 25 Apr 2019

Cited by 3 | Viewed by 4539

Abstract

In 2015–2016, South America went through the largest Zika epidemic in recorded history. One important aspect of this epidemic was the importance of sexual transmission in combination with the usual vectorial transmission, with asymmetrical transmissibilities between sexual partners depending on the type of [...] Read more.

In 2015–2016, South America went through the largest Zika epidemic in recorded history. One important aspect of this epidemic was the importance of sexual transmission in combination with the usual vectorial transmission, with asymmetrical transmissibilities between sexual partners depending on the type of sexual contact; this asymmetry manifested itself in data as an increased risk to women. We propose a mathematical model for the transmission of the Zika virus including sexual transmission via all forms of sexual contact, as well as vector transmission, assuming a constant availability of mosquitoes. From this model, we derive an expression for

R_{0}

, which is used to study and analyze the relative contributions of the male to female sexual transmission route vis-à-vis vectorial transmission. We also perform Bayesian inference of the model’s parameters using data from the 2016 Zika epidemic in Rio de Janeiro. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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11 pages, 242 KiB

Open AccessArticle

Zika Outbreak Emergency Preparedness and Response of Malaysian Private Healthcare Professionals: Are They Ready?

by Kingston Rajiah, Mari Kannan Maharajan, Pua Yin Yin, Yap Wei Yee, Wong Wan Lin and Chew Hui Kean

Microorganisms 2019, 7(3), 87; https://doi.org/10.3390/microorganisms7030087 - 19 Mar 2019

Cited by 13 | Viewed by 4745

Abstract

Zika virus has been declared as a public health emergency of international concern. The Center for Disease Control and Prevention has issued guidelines reminding healthcare workers about the importance of taking steps to prevent the spread of Zika virus, how to test and [...] Read more.

Zika virus has been declared as a public health emergency of international concern. The Center for Disease Control and Prevention has issued guidelines reminding healthcare workers about the importance of taking steps to prevent the spread of Zika virus, how to test and isolate patients suspected of carrying the Zika virus, and how to protect themselves from infection. Therefore, it is of utmost importance for healthcare professionals to be fully aware of Zika virus preparedness, and response measures should an outbreak occur in Malaysia in order to quickly and efficiently contain the outbreak, ensure the safety of individual or healthcare personnel safety, as well as to prevent further spreading of the disease. This research aims to show how prepared Malaysian healthcare professionals are against Zika virus and how well can they respond during an outbreak. In total, 504 healthcare professionals (128 general practitioners, 215 community pharmacists, 161 nurses) from private health clinics were the target population of the four states of Malaysia where Zika cases suspected. The sample size of each category was calculated by using a formula for estimating the population proportion. An additional 10% of the calculated sample size was added to compensate the non-response rate. The Center For Disease Control and Prevention and World Health Organisation provided a checklist to assess how prepared healthcare professionals are for an Zika outbreak. This checklist was modified to a questionnaire in order to assess health care professionals’ preparedness and response to the Zika outbreak. Community pharmacists are still lacking in their preparedness and perceived response to the Zika outbreak compared to the general practitioners in the private sector. Hence community pharmacists should attend training given by the Ministry of Health Malaysia as a continuing education, which may help them to respond during a Zika outbreak. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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25 pages, 1861 KiB

Open AccessReview

Protective or Detrimental? Understanding the Role of Host Immunity in Leishmaniasis

by Camila dos Santos Meira and Lashitew Gedamu

Microorganisms 2019, 7(12), 695; https://doi.org/10.3390/microorganisms7120695 - 13 Dec 2019

Cited by 33 | Viewed by 10689

Abstract

The intracellular protozoan parasites of the genus Leishmania are the causative agents of leishmaniasis, a vector-borne disease of major public health concern, estimated to affect 12 million people worldwide. The clinical manifestations of leishmaniasis are highly variable and can range from self-healing localized [...] Read more.

The intracellular protozoan parasites of the genus Leishmania are the causative agents of leishmaniasis, a vector-borne disease of major public health concern, estimated to affect 12 million people worldwide. The clinical manifestations of leishmaniasis are highly variable and can range from self-healing localized cutaneous lesions to life-threatening disseminated visceral disease. Once introduced into the skin by infected sandflies, Leishmania parasites interact with a variety of immune cells, such as neutrophils, monocytes, dendritic cells (DCs), and macrophages. The resolution of infection requires a finely tuned interplay between innate and adaptive immune cells, culminating with the activation of microbicidal functions and parasite clearance within host cells. However, several factors derived from the host, insect vector, and Leishmania spp., including the presence of a double-stranded RNA virus (LRV), can modulate the host immunity and influence the disease outcome. In this review, we discuss the immune mechanisms underlying the main forms of leishmaniasis, some of the factors involved with the establishment of infection and disease severity, and potential approaches for vaccine and drug development focused on host immunity. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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11 pages, 591 KiB

Open AccessReview

Pathogenesis and Immune Response Caused by Vector-Borne and Other Viral Infections in a Tupaia Model

by Mohammad Enamul Hoque Kayesh, Md Abul Hashem, Bouchra Kitab and Kyoko Tsukiyama-Kohara

Microorganisms 2019, 7(12), 686; https://doi.org/10.3390/microorganisms7120686 - 12 Dec 2019

Cited by 7 | Viewed by 3535

Abstract

The Tupaia or tree shrew (Tupaia belangeri), a small mammal of the Tupaiidae family, is an increasingly used and promising infection model for virological and immunological research. Recently, sequencing of the Tupaia whole genome revealed that it is more homologous to [...] Read more.

The Tupaia or tree shrew (Tupaia belangeri), a small mammal of the Tupaiidae family, is an increasingly used and promising infection model for virological and immunological research. Recently, sequencing of the Tupaia whole genome revealed that it is more homologous to the genome of humans than of rodents. Viral infections are a global threat to human health, and a complex series of events are involved in the interactions between a virus and the host immune system, which play important roles in the activation of an immune response and the outcome of an infection. Majority of immune response data in viral infections are obtained from studies using animal models that enhance the understanding of host-virus interactions; a proper understanding of these interactions is very important for the development of effective antivirals and prophylactics. Therefore, animal models that are permissive to infection and that recapitulate human disease pathogenesis and immune responses to viral infections are essential. Several studies have shown the permissiveness of Tupaia to a number of important human viral infections in vitro and in vivo without prior adaptation of the viruses; the immune responses and clinical manifestations were comparable to those observed in human infections. Thus, the Tupaia is being utilized and developed as a promising immunocompetent small animal model for viral infection studies. In this review, we focused on the immune responses, mostly innate, during viral infection and pathogenesis in the Tupaia model; we evaluated the interaction between the virus and the components of host resistance, the usefulness of this model for immunopathogenesis studies, and the vaccines and antivirals available. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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21 pages, 1855 KiB

Open AccessReview

Malaria in North-East India: Importance and Implications in the Era of Elimination

by Devojit Kumar Sarma, Pradumnya Kishore Mohapatra, Dibya Ranjan Bhattacharyya, Savitha Chellappan, Balasubramani Karuppusamy, Keshab Barman, Nachimuthu Senthil Kumar, Aditya Prasad Dash, Anil Prakash and Praveen Balabaskaran Nina

Microorganisms 2019, 7(12), 673; https://doi.org/10.3390/microorganisms7120673 - 10 Dec 2019

Cited by 32 | Viewed by 8880

Abstract

Worldwide and in India, malaria elimination efforts are being ramped up to eradicate the disease by 2030. Malaria elimination efforts in North-East (NE) India will have a great bearing on the overall efforts to eradicate malaria in the rest of India. The first [...] Read more.

Worldwide and in India, malaria elimination efforts are being ramped up to eradicate the disease by 2030. Malaria elimination efforts in North-East (NE) India will have a great bearing on the overall efforts to eradicate malaria in the rest of India. The first cases of chloroquine and sulfadoxine-pyrimethamine resistance were reported in NE India, and the source of these drug resistant parasites are most likely from South East Asia (SEA). NE India is the only land route through which the parasites from SEA can enter the Indian mainland. India’s malaria drug policy had to be constantly updated due to the emergence of drug resistant parasites in NE India. Malaria is highly endemic in many parts of NE India, and Plasmodium falciparum is responsible for the majority of the cases. Highly efficient primary vectors and emerging secondary vectors complicate malaria elimination efforts in NE India. Many of the high transmission zones in NE India are tribal belts, and are difficult to access. The review details the malaria epidemiology in seven NE Indian states from 2008 to 2018. In addition, the origin and evolution of resistance to major anti-malarials are discussed. Furthermore, the bionomics of primary vectors and emergence of secondary malaria vectors, and possible strategies to prevent and control malaria in NE are outlined. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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28 pages, 1349 KiB

Open AccessReview

Contemporary Strategies and Current Trends in Designing Antiviral Drugs against Dengue Fever via Targeting Host-Based Approaches

by Foysal Ahammad, Tengku Rogayah Tengku Abd Rashid, Maizan Mohamed, Suriyea Tanbin and Fazia Adyani Ahmad Fuad

Microorganisms 2019, 7(9), 296; https://doi.org/10.3390/microorganisms7090296 - 28 Aug 2019

Cited by 30 | Viewed by 14290

Abstract

Dengue virus (DENV) is an arboviral human pathogen transmitted through mosquito bite that infects an estimated ~400 million humans (~5% of the global population) annually. To date, no specific therapeutics have been developed that can prevent or treat infections resulting from this pathogen. [...] Read more.

Dengue virus (DENV) is an arboviral human pathogen transmitted through mosquito bite that infects an estimated ~400 million humans (~5% of the global population) annually. To date, no specific therapeutics have been developed that can prevent or treat infections resulting from this pathogen. DENV utilizes numerous host molecules and factors for transcribing the single-stranded ~11 kb positive-sense RNA genome. For example, the glycosylation machinery of the host is required for viral particles to assemble in the endoplasmic reticulum. Since a variety of host factors seem to be utilized by the pathogens, targeting these factors may result in DENV inhibitors, and will play an important role in attenuating the rapid emergence of other flaviviruses. Many experimental studies have yielded findings indicating that host factors facilitate infection, indicating that the focus should be given to targeting the processes contributing to pathogenesis along with many other immune responses. Here, we provide an extensive literature review in order to elucidate the progress made in the development of host-based approaches for DENV viral infections, focusing on host cellular mechanisms and factors responsible for viral replication, aiming to aid the potential development of host-dependent antiviral therapeutics. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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13 pages, 879 KiB

Open AccessReview

West Nile Virus and Usutu Virus Co-Circulation in Europe: Epidemiology and Implications

by Silvia Zannoli and Vittorio Sambri

Microorganisms 2019, 7(7), 184; https://doi.org/10.3390/microorganisms7070184 - 26 Jun 2019

Cited by 66 | Viewed by 5982

Abstract

West Nile virus (WNV) and Usutu virus (USUV) are neurotropic mosquito-borne flaviviruses that may infect humans. Although WNV is much more widespread and plays a much larger role in human health, the two viruses are characterized by similar envelope antigens, clinical manifestations, and [...] Read more.

West Nile virus (WNV) and Usutu virus (USUV) are neurotropic mosquito-borne flaviviruses that may infect humans. Although WNV is much more widespread and plays a much larger role in human health, the two viruses are characterized by similar envelope antigens, clinical manifestations, and present overlapping in terms of geographic range of transmission, host, and vector species. This review highlights some of the most relevant aspects of WNV and USUV human infections in Europe, and the possible implications of their co-circulation. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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26 pages, 862 KiB

Open AccessReview

Arthritogenic Alphaviruses: A Worldwide Emerging Threat?

by Laura I. Levi and Marco Vignuzzi

Microorganisms 2019, 7(5), 133; https://doi.org/10.3390/microorganisms7050133 - 14 May 2019

Cited by 51 | Viewed by 7342

Abstract

Arthritogenic alphaviruses are responsible for a dengue-like syndrome associated with severe debilitating polyarthralgia that can persist for months or years and impact life quality. Chikungunya virus is the most well-known member of this family since it was responsible for two worldwide epidemics with [...] Read more.

Arthritogenic alphaviruses are responsible for a dengue-like syndrome associated with severe debilitating polyarthralgia that can persist for months or years and impact life quality. Chikungunya virus is the most well-known member of this family since it was responsible for two worldwide epidemics with millions of cases in the last 15 years. However, other arthritogenic alphaviruses that are as of yet restrained to specific territories are the cause of neglected tropical diseases: O’nyong’nyong virus in Sub-Saharan Africa, Mayaro virus in Latin America, and Ross River virus in Australia and the Pacific island countries and territories. This review evaluates their emerging potential in light of the current knowledge for each of them and in comparison to chikungunya virus. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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11 pages, 901 KiB

Open AccessOpinion

Broader Geographical Distribution of Toscana Virus in the Mediterranean Region Suggests the Existence of Larger Varieties of Sand Fly Vectors

by Nazli Ayhan, Jorian Prudhomme, Lison Laroche, Anne-Laure Bañuls and Remi N. Charrel

Microorganisms 2020, 8(1), 114; https://doi.org/10.3390/microorganisms8010114 - 14 Jan 2020

Cited by 33 | Viewed by 4832

Abstract

Toscana virus (TOSV) is endemic in the Mediterranean basin, where it is transmitted by sand flies. TOSV can infect humans and cause febrile illness as well as neuroinvasive infections affecting the central and peripheral nervous systems. Although TOSV is a significant human pathogen, [...] Read more.

Toscana virus (TOSV) is endemic in the Mediterranean basin, where it is transmitted by sand flies. TOSV can infect humans and cause febrile illness as well as neuroinvasive infections affecting the central and peripheral nervous systems. Although TOSV is a significant human pathogen, it remains neglected and there are consequently many gaps of knowledge. Recent seroepidemiology studies and case reports showed that TOSV’s geographic distribution is much wider than was assumed a decade ago. The apparent extension of the TOSV circulation area raises the question of the sandfly species that are able to transmit the virus in natural conditions. Phlebotomus (Ph.) perniciosus and Ph. perfiliewi were historically identified as competent species. Recent results suggest that other species of sand flies could be competent for TOSV maintenance and transmission. Here we organize current knowledge in entomology, epidemiology, and virology supporting the possible existence of additional phlebotomine species such as Ph. longicuspis, Ph. sergenti, Ph. tobbi, Ph. neglectus, and Sergentomyia minuta in TOSV maintenance. We also highlight some of the knowledge gaps to be addressed in future studies. Full article

(This article belongs to the Special Issue Emerging Vector Borne Infections: A Novel Threat for Global Health)

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