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Vector Borne and Zoonotic Diseases... Jul 2024In urban Thailand, arboviral infections dominate diagnoses of acute undifferentiated fevers (AUFs) owing to their well-defined epidemiology and characteristic clinical...
In urban Thailand, arboviral infections dominate diagnoses of acute undifferentiated fevers (AUFs) owing to their well-defined epidemiology and characteristic clinical presentations. However, rickettsial diseases, also endemic in this setting, remain under-recognized owing to challenges in early detection. This study aimed to identify potential rickettsial infections among patients with AUF in Bangkok and vicinity utilizing leftover nucleic acid extracted from serum samples from patients initially suspected of but negative for arbovirus infections. A total of 609 nucleic acid samples were screened for rickettsial bacteria using real-time PCR, targeting the 17-kDa common antigen gene of spp. and the 47-kDa gene of . Nine samples were positive for spp. and two were positive for . DNA sequence and phylogenetic analyses based on partial 17-kDa antigen and citrate synthase () genes identified the -positive samples as in eight cases and in one case. Analysis of the 56-kDa type-specific antigen gene identified the two isolates as Gilliam-related genotypes. Although rickettsial diseases typically present with mild symptoms, two patients with infection (murine typhus) developed respiratory distress syndrome, highlighting the potential for rare but serious complications. This study underscores the critical importance of differential diagnosis and prompt, effective intervention to prevent complications in suspected cases.
PubMed: 38946645
DOI: 10.1089/vbz.2024.0030 -
One Health Outlook Jul 2024Oropouche and Mayaro viruses are enzootic arboviruses of public health concern throughout Latin America. Recent outbreaks of OROV in northern region and sporadic...
Oropouche and Mayaro viruses are enzootic arboviruses of public health concern throughout Latin America. Recent outbreaks of OROV in northern region and sporadic autochthonous cases in western region of Brazil, suggest a silent circulation of these neglected viruses. Aiming to investigate the exposure of different species of domestic animals to MAYV and OROV in urban and peri-urban areas of West-Central Brazil, we performed a cross-sectional serosurvey by plaque reduction neutralization test (PRNT). Our findings included neutralizing antibodies for both arboviruses in cattle, dogs and horses, suggesting eventual role of domestic animals in enzootic arbovirus surveillance in Brazil.
PubMed: 38946009
DOI: 10.1186/s42522-024-00104-w -
International Journal For Parasitology.... Jun 2024Leishmania major is responsible for zoonotic cutaneous leishmaniasis. Therapy is mainly based on the use of antimony-based drugs; however, treatment failures and illness...
Leishmania major is responsible for zoonotic cutaneous leishmaniasis. Therapy is mainly based on the use of antimony-based drugs; however, treatment failures and illness relapses were reported. Although studies were developed to understand mechanisms of drug resistance, the interactions of resistant parasites with their reservoir hosts and vectors remain poorly understood. Here we compared the development of two L. major MON-25 trivalent antimony-resistant lines, selected by a stepwise in vitro Sb(III)-drug pressure, to their wild-type parent line in the natural vector Phlebotomus papatasi. The intensity of infection, parasite location and morphological forms were compared by microscopy. Parasite growth curves and IC values have been determined before and after the passage in Ph. papatasi. qPCR was used to assess the amplification rates of some antimony-resistance gene markers. In the digestive tract of sand flies, Sb(III)-resistant lines developed similar infection rates as the wild-type lines during the early-stage infections, but significant differences were observed during the late-stage of the infections. Thus, on day 7 p. i., resistant lines showed lower representation of heavy infections with colonization of the stomodeal valve and lower percentage of metacyclic promastigote forms in comparison to wild-type strains. Observed differences between both resistant lines suggest that the level of Sb(III)-resistance negatively correlates with the quality of the development in the vector. Nevertheless, both resistant lines developed mature infections with the presence of infective metacyclic forms in almost half of infected sandflies. The passage of parasites through the sand fly guts does not significantly influence their capacity to multiply in vitro. The IC values and molecular analysis of antimony-resistance genes showed that the resistant phenotype of Sb(III)-resistant parasites is maintained after passage through the sand fly. Sb(III)-resistant lines of L. major MON-25 were able to produce mature infections in Ph. papatasi suggesting a possible circulation in the field using this vector.
PubMed: 38941845
DOI: 10.1016/j.ijpddr.2024.100554 -
Euro Surveillance : Bulletin Europeen... Jun 2024Oropouche fever is caused by Oropouche virus (OROV), transmitted primarily through the bite of infected midges, particularly of the genus . The virus is mainly...
Oropouche fever is caused by Oropouche virus (OROV), transmitted primarily through the bite of infected midges, particularly of the genus . The virus is mainly circulating in Central and South America where several countries reported an ongoing outbreak. We report here two imported cases of OROV infection identified in Italy, late May-early June 2024. These cases indicate that in the shadow of a massive dengue outbreak in the Americas, the Oropouche outbreak might be more widespread than previously estimated.
Topics: Humans; Italy; Travel; Male; Cuba; Adult; Orthobunyavirus; Animals; Disease Outbreaks; Bunyaviridae Infections; Middle Aged; Female
PubMed: 38940002
DOI: 10.2807/1560-7917.ES.2024.29.26.2400362 -
PLoS Neglected Tropical Diseases Jun 2024Usutu virus (USUV) is a zoonotic arbovirus infecting mainly wild birds. It is transmitted by ornithophilic mosquitoes, mainly of the genus Culex from birds to birds and...
Usutu virus (USUV) is a zoonotic arbovirus infecting mainly wild birds. It is transmitted by ornithophilic mosquitoes, mainly of the genus Culex from birds to birds and to several vertebrate dead-end hosts. Several USUV lineages, differing in their virulence have emerged in the last decade and now co-circulate in Europe, impacting human populations. However, their relative transmission and effects on their mosquito vectors is still not known. We thus compared the vector competence and survival of Culex pipiens mosquitoes experimentally infected with two distinct USUV lineages, EU2 and EU3, that are known to differ in their virulence and replication in vertebrate hosts. Infection rate was variable among blood feeding assays but variations between EU2 and EU3 lineages were consistent suggesting that Culex pipiens was equally susceptible to infection by both lineages. However, EU3 viral load increased with viral titer in the blood meal while EU2 viral load was high at all titers which suggest a greater replication of EU2 than EU3 in mosquito. While their relative transmission efficiencies are similar, at least at low blood meal titer, positive correlation between transmission and blood meal titer was observed for EU3 only. Contrary to published results in vertebrates, EU3 induced a higher mortality to mosquitoes (i.e. virulence) than EU2 whatever the blood meal titer. Therefore, we found evidence of lineage-specific differences in vectorial capacity and virulence to both the vector and vertebrate host which lead to balanced propagation of both viral lineages. These results highlight the need to decipher the interactions between vectors, vertebrate hosts, and the diversity of arbovirus lineages to fully understand transmission dynamics.
PubMed: 38935783
DOI: 10.1371/journal.pntd.0012295 -
Emerging Microbes & Infections Jun 2024Chikungunya virus has caused millions of cases worldwide over the last twenty years, with recent outbreaks in Kedougou region in the southeastern Senegal, West Africa....
Chikungunya virus has caused millions of cases worldwide over the last twenty years, with recent outbreaks in Kedougou region in the southeastern Senegal, West Africa. Genomic characterization highlights that an ongoing epidemic in Kedougou in 2023 is not due to an introduction event but caused by the re-emergence of an endemic strain evolving linearly in a sylvatic context.
PubMed: 38934257
DOI: 10.1080/22221751.2024.2373308 -
Antibody Therapeutics Apr 2024Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, escape coronavirus disease 2019 therapeutics and vaccines, and jeopardize public...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve, escape coronavirus disease 2019 therapeutics and vaccines, and jeopardize public health. To combat SARS-CoV-2 antigenic escape, we developed a rapid, high-throughput pipeline to discover monospecific VHH antibodies and iteratively develop VHH-Fc-VHH bispecifics capable of neutralizing emerging SARS-CoV-2 variants. By panning VHH single-domain phage libraries against ancestral or beta spike proteins, we discovered high-affinity VHH antibodies with unique target epitopes. Combining two VHHs into a tetravalent bispecific construct conferred broad neutralization activity against multiple variants and was more resistant to antigenic escape than the monospecific antibody alone. Following the rise of the Omicron variant, a VHH in the original bispecific construct was replaced with another VHH discovered against the Omicron BA.1 receptor binding domain; the resulting bispecific exhibited neutralization against both BA.1 and BA.5 sublineage variants. A heavy chain-only tetravalent VHH-Fc-VHH bispecific platform derived from humanized synthetic libraries held a myriad of unique advantages: (i) synthetic preconstructed libraries minimized risk of liabilities and maximized discovery speed, (ii) VHH scaffolds allowed for a modular "plug-and-play" format that could be rapidly iterated upon as variants of concern arose, (iii) natural dimerization of single VHH-Fc-VHH polypeptides allowed for straightforward bispecific production and purification methods, and (iv) multivalent approaches enhanced avidity boosting effects and neutralization potency, and conferred more robust resistance to antigenic escape than monovalent approaches against specific variants. This iterative platform of rapid VHH discovery combined with modular bispecific design holds promise for long-term viral control efforts.
PubMed: 38933534
DOI: 10.1093/abt/tbae009 -
Viruses Jun 2024Dugbe virus (DUGV) is a tick-borne arbovirus first isolated in Nigeria in 1964. It has been detected in many African countries using such diverse methods as serological...
Dugbe virus (DUGV) is a tick-borne arbovirus first isolated in Nigeria in 1964. It has been detected in many African countries using such diverse methods as serological tests, virus isolation, and molecular detection. In Senegal, reports of DUGV isolates mainly occurred in the 1970s and 1980s. Here, we report a contemporary detection of three novel DUGV isolates upon screening of a total of 2877 individual ticks regrouped into 844 pools. The three positive pools were identified as , the main known vector of DUGV, collected in the southern part of the country (Kolda region). Interestingly, phylogenetic analysis indicates that the newly sequenced isolates are globally related to the previously characterized isolates in West Africa, thus highlighting potentially endemic, unnoticed viral transmission. This study was also an opportunity to develop a rapid and affordable protocol for full-genome sequencing of DUGV using nanopore technology. The results suggest a relatively low mutation rate and relatively conservative evolution of DUGV isolates.
Topics: Animals; Senegal; Phylogeny; Genome, Viral; Ticks; Amblyomma; Arboviruses
PubMed: 38932256
DOI: 10.3390/v16060964 -
Viruses Jun 2024Brazil has earned the moniker "arbovirus hotspot", providing an ideal breeding ground for a multitude of arboviruses thriving in various zoonotic and urban cycles. As... (Review)
Review
Brazil has earned the moniker "arbovirus hotspot", providing an ideal breeding ground for a multitude of arboviruses thriving in various zoonotic and urban cycles. As the planet warms and vectors expand their habitat range, a nuanced understanding of lesser-known arboviruses and the factors that could drive their emergence becomes imperative. Among these viruses is the Iguape virus (IGUV), a member of the species, which was first isolated in 1979 from a sentinel mouse in the municipality of Iguape, within the Vale do Ribeira region of São Paulo State. While evidence suggests that IGUV circulates among birds, wild rodents, marsupials, bats, and domestic birds, there is no information available on its pathogenesis in both humans and animals. The existing literature on IGUV spans decades, is outdated, and is often challenging to access. In this review, we have curated information from the known literature, clarifying its elusive nature and investigating the factors that may influence its emergence. As an , IGUV poses a potential threat, which demands our attention and vigilance, considering the serious outbreaks that the Zika virus, another neglected orthoflavivirus, has unleashed in the recent past.
Topics: Animals; Brazil; Flavivirus; Humans; Flavivirus Infections; Phylogeny; Mice; Birds
PubMed: 38932252
DOI: 10.3390/v16060960 -
Viruses May 2024The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector...
The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector () is an enigma. An immunologically naïve population of over 2 billion resides in Asia, with most regions infested with the urban YF vector. One hypothesis for the lack of Asian YF, and absence of urban YF in the Americas for over 80 years, is that prior immunity to related flaviviruses like dengue (DENV) or Zika virus (ZIKV) modulates YFV infection and transmission dynamics. Here we utilized an interferon α/β receptor knock-out mouse model to determine the role of pre-existing dengue-2 (DENV-2) and Zika virus (ZIKV) immunity in YF virus infection, and to determine mechanisms of cross-protection. We utilized African and Brazilian YF strains and found that DENV-2 and ZIKV immunity significantly suppresses YFV viremia in mice, but may or may not protect relative to disease outcomes. Cross-protection appears to be mediated mainly by humoral immune responses. These studies underscore the importance of re-assessing the risks associated with YF outbreak while accounting for prior immunity from flaviviruses that are endemic.
Topics: Animals; Yellow Fever; Mice; Cross Protection; Disease Models, Animal; Yellow fever virus; Zika Virus; Mice, Knockout; Zika Virus Infection; Dengue Virus; Receptor, Interferon alpha-beta; Antibodies, Viral; Flavivirus; Aedes; Dengue; Female; Viremia; Mosquito Vectors; Flavivirus Infections; Mice, Inbred C57BL
PubMed: 38932129
DOI: 10.3390/v16060836