Biology subjects

Temmam, S.

Publications and source records attributed to Temmam, S..

4 recordsLinked to original sources

bioRxiv2025

Detection and phylogenetic characterization of Jingmen tick virus in Amblyomma mixtum ticks from Costa Rica

Jingmenvirus is a group of segmented flaviviruses detected in arthropods and vertebrates that has attracted growing public health interest due to the recognition of some members as emerging human arboviral pathogens. As part of a study aimed at deciphering the virome of medically and veterinary important ticks in Costa Rica, we detected Jingmen tick virus (JMTV) in engorged Amblyomma mixtum ticks collected from horses. We assembled three complete genome segments and one partial segment from tick pools. Phylogenetic analyses revealed that JMTV from Costa Rica (JMTV Costa Rica) shares a common viral ancestor with JMTV viruses identified in ticks from the Caribbean and Latin America, with putative reassortment events detected across segments. Two distinct clades of Jingmen viruses were identified in the American continent, suggesting two distinct introductions: one from Europe/Asia and the other from Africa/Asia. Of note, JMTV Costa Rica falls in the same clade as viruses from Europe and Turkey, including sequences found in humans. Our study constitutes the first report of JMTV associated with Amblyomma mixtum. This tick species feeds on a wide range of hosts, including wildlife, domestic animals, and frequently parasitizes humans in Central America. Further research involving the detection of active or past infections in humans and horses after tick bites are needed to evaluate the risk of JMTV-associated arboviral infection in Central America, including Costa Rica. ImportanceJingmenviruses are flaviviruses detected in arthropods and vertebrates reported in several countries worldwide. Some members cause disease and infections in humans; therefore, they are considered emergent human arboviruses. In Costa Rica and Central America, there is no information on tick-associated viruses or the role of ticks as putative vectors of viruses. Here, we report the first regional detection of Jingmen tick virus (JMTV) in Amblyomma mixtum ticks collected from horses. We assembled three complete and one partial viral segment from tick pools. Phylogenetic analysis revealed that the JTMV detected in Costa Rica is closely related to other detections from Latin America and the Caribbean and is located in the same clade as viruses reported in humans. Additionally, we detected two separate introductions of JMTV to Latin America. To determine whether this JMTV is an emergent arbovirus, research on past or active infections in humans is required.

microbiology↗

bioRxiv2025

Fluke-borne viruses are a risk factor for diseases caused by carcinogenic trematodes

Three trematode parasites, Schistosoma haematobium, Opisthorchis viverrini, and Clonorchis sinensis are recognized group 1 carcinogens for their roles in squamous cell carcinoma of the urinary bladder and bile duct cancer (cholangiocarcinoma). We aimed to assess the presence of fluke viruses and their association with malignancy in fluke infections. We showed that all three carcinogenic trematodes harbored related viruses. Focusing on O. viverrini, we observed virus persistence at discrete life stages and viral tropism for the fluke tegument, and we provided molecular and serological evidence of parasitized hosts exposure to viral RNA and proteins. Serological analyses confirmed seroconversion of residents in endemic sites and revealed that antibody titers and avidity against fluke-borne viruses increase in individuals with hepatobiliary diseases. Random forest models discriminated efficiently between liver-fluke-infected participants without disease and those with periductal fibrosis or cholangiocarcinoma. Thus, we show that fluke-borne viruses are risk factors and diagnostic targets for fluke-associated cancer.

microbiology↗

bioRxiv2025

Entry, replication and innate immunity evasion of BANAL-236, a SARS-CoV-2-related bat virus, in Rhinolophus and human cells

Asian Rhinolophus bats are considered the natural reservoirs of an ancestral SARS-CoV-2. However, the biology of SARS-CoV-2-related viruses in bat cells is not well understood. Here, we investigated the replication of BANAL-236, the only bat-derived SARS-CoV-2 relative isolated to date, in Rhinolophus cells. BANAL-236 did not replicate in wild-type Rhinolophus cell lines. Entry assays using pseudoviruses expressing the spike proteins (S) of SARS-CoV-2, BANAL-236, and BANAL-52 revealed that efficient S-mediated entry depends on the expression of human ACE2 (hACE2) and human TMPRSS2 (hTMPRSS2) in human and Rhinolophus cells. Expression of Rhinolophus entry factors, either alone or in combination, did not facilitate SARS-CoV-2 or BANAL-236 entry in human cells, suggesting that the S protein of BANAL-236 interacts more efficiently with hACE2 than with its Rhinolophus counterpart (rACE2). Through biochemical, virological, and electron microscopy analyses, we showed that BANAL-236 and SARS-CoV-2 completed their replication cycles in a Rhinolophus cell line engineered to express high levels of hACE2 and hTMPRSS2. Despite efficient viral replication in modified Rhinolophus and human cells, no induction of interferon (IFN)-stimulated genes was detected. Using a screening approach, we identified several BANAL-236 proteins that antagonize IFN production and signaling in human cells. Our findings thus show that BANAL-236 possesses critical features that enabled zoonotic spillover: hACE2 usage and potent evasion of human IFN responses. The Rhinolophus cellular model we established offers a platform for further investigating the interactions between bat coronaviruses and their reservoir hosts. Author summaryBats are known reservoirs for viruses that cause severe diseases in humans, such as coronaviruses and filoviruses. Bat species naturally or experimentally infected with these viruses rarely exhibit clinical symptoms, suggesting an evolved tolerance to viral infections. To elucidate the mechanisms underlying viral tolerance and to identify factors that could facilitate zoonotic spillover, it is essential to study the replication of bat-borne viruses in relevant bat cellular models. Here, we investigated the replication of BANAL-236, a SARS-CoV-2 related virus isolated from fecal samples of Rhinolophus bats in Northen Laos, in a novel cell line derived from Rhinolophus ferrumequinum lung fibroblasts. Our findings reveal that BANAL-236 can efficiently use human entry factors and potently evade the human innate immune response, two traits that may have contributed to its zoonotic transmission. Furthermore, the R. ferrumequinum cell lines we developed is a valuable model for investigating the molecular interactions between sarbecoviruses and their natural hosts.

microbiology↗

bioRxiv2020

Absence of SARS-CoV-2 infection in cats and dogs in close contact with a cluster of COVID-19 patients in a veterinary campus

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which originated in Wuhan, China, in 2019, is responsible for the COVID-19 pandemic. It is now accepted that the wild fauna, probably bats, constitute the initial reservoir of the virus, but little is known about the role pets can play in the spread of the disease in human communities, knowing the ability of SARS-CoV-2 to infect some domestic animals. We tested 21 domestic pets (9 cats and 12 dogs) living in close contact with their owners (belonging to a veterinary community of 20 students) in which two students tested positive for COVID-19 and several others (n = 11/18) consecutively showed clinical signs (fever, cough, anosmia, etc.) compatible with COVID-19 infection. Although a few pets presented many clinical signs indicative for a coronavirus infection, no animal tested positive for SARS-CoV-2 by RT-PCR and no antibodies against SARS-CoV-2 were detectable in their blood using an immunoprecipitation assay. These original data can serve a better evaluation of the host range of SARS-CoV-2 in natural environment exposure conditions.

microbiology↗