West Nile Virus Fever Research Articles

Emergence of West Nile virus infection in Kerala, South India: A case of concern.

West Nile virus (WNV) infection is emerging as a disease of public health concern in Kerala, India with recurring outbreaks since 2011. With its tropical climate, biodiversity hot spots of Western ghats, forest cover, plenty of water bodies and bird sanctuaries, Kerala provides an ideal ecological niche for vector breeding and transmission of WNV. In this article, we reflect on the peculiar features of the outbreaks of WNV fever in Kerala and highlight the knowledge gaps, the research priorities and the need for effective control measures. Information on transmission patterns of WNV, its circulating lineages and identification of vectors is needed to adopt appropriate control strategies in the state. In addition to the active measures on the part of the health system to ensure vector control and to curtail transmission pathways of the disease, inclusion of the community in preventing WNV infection through awareness campaigns and other participatory control measures should be initiated in the pre-monsoon months.

Latin America's Dengue Outbreak Poses a Global Health Threat.

Dengue fever, caused by the dengue virus (DENV), poses a significant global health challenge, particularly in tropical and subtropical regions. Recent increases in indigenous DENV cases in Europe are concerning, reflecting rising incidence linked to climate change and the spread of Aedes albopictus mosquitoes. These vectors thrive under environmental conditions like temperature and humidity, which are increasingly influenced by climate change. Additionally, global travel accelerates the cross-border spread of mosquito-borne diseases. DENV manifests clinically in a spectrum from asymptomatic cases to severe conditions like dengue hemorrhagic fever and dengue shock syndrome, influenced by viral serotype and host factors. In 2024, Brazil experienced a fourfold increase in dengue cases compared to 2023, accompanied by higher mortality. Conventional control measures, such as vector control, community engagement, and vaccination, proved insufficient as climate change exacerbated mosquito proliferation, challenging containment efforts. In this regard, our review analyzes prevention measures and therapeutic protocols during the outbreak while addressing DENV transmission dynamics, clinical presentations, and epidemiological shifts. It also evaluates diagnostic strategies combining clinical assessment with serological and molecular testing, providing information to improve diagnostic and preventive measures. The global expansion of dengue-endemic regions, including outbreaks in Europe, highlights the urgent need for enhanced surveillance, proactive interventions, and international collaboration to mitigate the growing threat of Dengue and other arboviruses like West Nile, Zika, Chikungunya, Oropouche, and Yellow Fever viruses.

Characterization of Culicoides and mosquito fauna at the National Zoological Garden of Rabat, Morocco

Zoos are considering to be essential places for the conservation of wild animal species. It is essential to prevent their infection by pathogens especially for those belonging to threatened or extinct species. Zoo captive animals are susceptible to several Culicoides and mosquito borne-viruses. In order to further evaluate the risk of pathogen transmission in zoos, it is essential to identify the presence of potential vector species, as well as the animals bitten by those vectors.For this purpose, Culicoides and mosquito species composition was investigated in ten sites from March to June 2021 for Culicoides (18 collection nights) and in four sites from April to June 2022 for mosquitoes (16 collection nights) at the National Zoological Garden of Rabat (ZGR), Morocco. Culicoides (Diptera: Ceratopogonidae) were collected using Onderstepoort Veterinary Institute traps (UV-light/suction traps (OVI type)), every two weeks. Mosquitoes (Diptera: Culicidae) were collected using BG-Pro mosquito trap (BGP) combined with a CO2 source as an attractant, on two consecutive days every two weeks. The blood meal of engorged Culicoides was amplified by PCR, sequenced, and blasted for host species identification.In total, 1584 individuals belonging to the Culicoides genus were collected (88.25 % females and 11.75 % males) belonging to at least 13 different species. Among the species collected, Culicoides newsteadi (33.28 %), C. imicola (23.74 %), C. circumscriptus (18.88 %) and C. obsoletus/C. scoticus (7.96 %) constituted the majority of the total catches. These species are proven or suspected vector species of bluetongue and African hose sickness viruses in the Mediterranean basin. For mosquitoes, 455 individuals belonging to four species of three genera were collected (97.58 % females and 2.42 % males): Culex pipiens s.l. (94.29 %) (vector species of West Nile and Rift Valley fever viruses), Culiseta longiareolata (4.81 %), Aedes detritus s.l. and Ae. caspius (representing together less than 1.00 %). The results of blood meal analyses revealed that Culicoides fed on humans (n = 7), camels (n = 2), and common eland (n = 2).The composition of Culicoides and mosquito fauna is characteristic of the Rabat region. The composition is thus mostly determined by the environment rather than by the animal species presence. The results highlighted that Culicoides fed on humans and ruminants. It is therefore likely that the zoo's animals could be threatened by arboviruses transmitted by domestic animals in the region. Particular attention must be paid to the prevention of vector-borne diseases to ensure the proper conservation of species.

Malaria mosquitoes, Plasmodium parasites and skin microbiota, towards control of malaria: A review

Vector-borne pathogens are transmitted by bites of infected arthropod species. The pathogens require two different host species to complete their lifecycle, usually a vertebrate and an invertebrate host, of which the latter transmits the pathogen between vertebrate hosts. Blood-feeding mosquitoes are important vectors of several human pathogens, including arboviruses namely: chikungunya, dengue fever, Rift Valley fever, yellow fever and Zika transmitted by Aedes mosquitoes amongst others. Culex mosquitoes on the other hand transmit Saint Louis and Japanese encephalitis, lymphatic filariasis, West Nile fever and Rift Valley Fever virus while Anopheles mosquitoes transmit malaria. The contact rate between vectors and their vertebrate hosts affects the intensity of pathogen transmission, and hence disease epidemiology. The ability of vectors to locate their blood hosts therefore is crucial in disease maintenance and perseverance. Host odour is known to play an important role in mosquito host-seeking behaviour and hence influences the contact rate between vectors and hosts. This literature review focuses on interactions between malaria parasites, humans, mosquitoes and how skin bacterial volatiles mediate host-seeking behaviour of mosquitoes.

Detection of anti-premembrane antibody as a specific marker of four flavivirus serocomplexes and its application to serosurveillance in endemic regions

ABSTRACT In the past few decades, several emerging/re-emerging mosquito-borne flaviviruses have resulted in disease outbreaks of public health concern in the tropics and subtropics. Due to cross-reactivities of antibodies recognizing the envelope protein of different flaviviruses, serosurveillance remains a challenge. Previously we reported that anti-premembrane (prM) antibody can discriminate between three flavivirus infections by Western blot analysis. In this study, we aimed to develop a serological assay that can discriminate infection or exposure with flaviviruses from four serocomplexes, including dengue (DENV), Zika (ZIKV), West Nile (WNV) and yellow fever (YFV) viruses, and explore its application for serosurveillance in flavivirus-endemic countries. We employed Western blot analysis including antigens of six flaviviruses (DENV1, 2 and 4, WNV, ZIKV and YFV) from four serocomplexes. We tested serum samples from YF-17D vaccinees, and from DENV, ZIKV and WNV panels that had been confirmed by RT–PCR or by neutralization assays. The overall sensitivity/specificity of anti-prM antibodies for DENV, ZIKV, WNV, and YFV infections/exposure were 91.7%/96.4%, 91.7%/99.2%, 88.9%/98.3%, and 91.3%/92.5%, respectively. When testing 48 samples from Brazil, we identified multiple flavivirus infections/exposure including DENV and ZIKV, DENV and YFV, and DENV, ZIKV and YFV. When testing 50 samples from the Philippines, we detected DENV, ZIKV, and DENV and ZIKV infections with a ZIKV seroprevalence rate of 10%, which was consistent with reports of low-level circulation of ZIKV in Asia. Together, these findings suggest that anti-prM antibody is a flavivirus serocomplex-specific marker and can be employed to delineate four flavivirus infections/exposure in regions where multiple flaviviruses co-circulate.

Seroprevalence and Co-Circulation of Rift Valley Fever Virus and West Nile Fever Virus in Livestock Population of Afar Region, Northeast Ethiopia.

The distribution, epidemiology, and socioeconomic impact of Rift Valley fever (RVF) and West Nile (WN) viruses are poorly known in areas of sub-Saharan countries like Ethiopian pastoral region. The human and livestock density in the area has increased greatly in recent years, but little work has been done on arboviral diseases and their potential impact on human and livestock health. The aim of this study was to detect the circulation of zoonotic arboviruses such as Rift Valley fever virus and West Nile viruses in the livestock population and to estimate seroprevalence in Afar pastoral area northeast Ethiopia. Cross-sectional serological survey was carried out in 736 serum samples from which cattle (224), camel (155), goats (121), sheep (144), and donkeys (92) were tested for the presence of anti-RVFV and anti-WNV IgG using a competitive enzyme-linked immunosorbent assay (c-ELISA) in two purposively selected districts of the Afar region. The present study revealed a 9.1% (95% CI = 8.86-9.29) seroprevalence of co-circulation of RVF and WNV. High 32/155 (20.7%) seroprevalence of co-circulation was seen in camels, followed by goat 14/121 (11.6%), cattle 16/224 (7.14%), and sheep 5/144 (3.5%), respectively, and higher 41/421 (9.7%) seroprevalence of co-circulation was observed in Amibara district than Haruka district. Camels were seven times (OR: 7.016, 95% CI = 2.639-18.653) more likely to be seropositive for the co-circulation than sheep (p ≤ 0.001). Livestock herds found in Amibara district were 1.2 times (OR: 1.165, 95% CI = 0.680-1.996) more likely to be seropositive for RVFV infection than those in Haruka areas. Given the co-occurrence of RVFV and WNV circulations, along with often suboptimal human and animal health surveillance in many similar areas' attention should be given. Investigation of the potential socioeconomic and health impacts of zoonotic arbovirus infections in such areas is crucial. Since both RVFV and WNFV are transmitted through a mosquito vector, avoiding mosquito bites is the primary method of prevention.

Opsoclonus-myoclonus syndrome associated with West Nile virus

Opsoclonus is oculomotor dyskinesia characterized by rapid, repetitive conjugate eye movements that are involuntary, arrhythmic, chaotic, and multidirectional (horizontal, vertical, and torsional components). Most common cause of the symptom is paraneoplastic process. It is combined with myoclonus usually with the development of opsoclonus-myoclonus syndrome. Viral etiology is one of the possible causes of the of this syndrome, which is presented in the following case. A 26-year-old man was admitted to an infectious hospital suspected by encephalitis. After a 2-day febrile fever the patient developed balance problem, nausea, vomiting, tremors in the limbs and head, sensations of jerking of eyeballs. The neurological examination revealed opsoclonus, myoclonic jerking in the limbs, neck and trunk muscles, severe static and dynamic ataxia, there was no consciousness changes or altered mental stature. Cerebrospinal fluid examination revealed a pleocytosis (24 cells), increased protein levels (1.1 g/l). MRI of the brain was normal. After excluding of typical neuroinfections the patient was tested for West Nile fever. Elevated titers of IgG and IgM for West Nile fever virus were detected, as well as positive PCR for virus RNA in the cerebrospinal fluid. Patient was treated by acyclovir, an antibiotic and dexamethasone but severe neurological symptoms were persisted for 2 weeks with inability of sitting and walking. Then the symptoms gradually began to improve, rehabilitation was included with total recovery during the next 2 months. The doctors should be aware for possibility of neuroinvasive form of West Nile fever as the etiology of opsoclonus-myoclonus syndrome.

First Serological Evidence of West Nile Virus among Individuals with Febrile Illness in a Tertiary Hospital in Port Harcourt, Nigeria

Aims: West Nile Virus (WNV) infection can cause severe illness. Very little is known about the seroepidemiology of WNV infection in individuals with febrile illness in Nigeria and many other developing countries. This study was carried out to determine the seroprevalence of WNV in individuals with febrile illness attending a tertiary hospital in Port Harcourt, Nigeria and to determine if there was an association between WNV infection with age and sex.
 Study Design: Cross-Sectional Study
 Place and Duration of Study: Port Harcourt in Rivers State, Nigeria from September 2019 to December 2019.
 Methods: Human sera were obtained and WNV IgG was determined using the Enzyme-Linked Immunosorbent Assay (ELISA) technique.
 Results: Of the 90 study subjects tested, WNV IgG antibodies were present in 27 (30.0%) study participants while 63 (70.0%) study participants were seronegative for WNV IgG antibody. With age, a higher prevalence of WNV occurred among 61-70-year-olds (31.3%, n= 5) compared to 41-60 (30.8%, n= 12) and 20-40 (28.6%, n= 10). A higher prevalence of WNV IgG antibodies occurred in males (34.3%, n=12) than their female counterparts (30.9%, n=17). This study indicated that there is no association between WNV infection with age and sex.
 Conclusion and Recommendations: These results show that WNV is circulating in Rivers State and has accounted for malaria-like infection in the region. It is recommended that WNV serological testing for malaria-infected individuals should be included as a routine test since they are most likely to present similar symptoms of WNV fever. Also, proper hygiene which includes eliminating mosquito breeding sites is recommended to mitigate the spread of West Nile Virus infection.

A case of West Nile fever in the Kursk region of Russia

Aim: to analyze the features of the clinical course of a case of West Nile fever (WNF) first detected in the Kursk region. Materials and methods. The article presents the first case of WNF detected in the Kursk region, confirmed by detection of pathogen RNA in the PCR test. Results. Patient Ch., 68 years old, was hospitalized to the intensive care unit of the Regional Clinical Infectious Diseases Hospital with severe intoxication, fever up to 39°C, positive meningeal symptoms of Kernig, Brudzinsky, severe neck stiffness. Upon admission, the analysis of peripheral blood showed leukocytosis up to 13.6×109, lymphopenia up to 5%, ESR acceleration up to 20 mm/h. Biochemical analysis revealed a significant increase in CRP, an increase in transaminase activity. In the cerebrospinal fluid, cytosis was noted up to 71 cells per mm3, an increase in protein up to 872 mg/l, the number of neutrophils up to 60%, lymphocytes - up to 40%, and the loss of a delicate plaque. The results of the study revealed high titers of Ig M and Ig G to the antigens of the virus, as well as the detection of WNF virus RNA in the blood and cerebrospinal fluid by PCR. Taking into account the data of the epidemiological anamnesis, clinical symptoms, positive results of ELISA and PCR of blood and cerebrospinal fluid for the causative agent of WNF, the diagnosis was made: West Nile fever with CNS damage, meningeal form (serous meningitis), severe course. Dyscirculatory encephalopathy of complex (dyscirculatory, dysmetabolic) genesis with scattered microsymptomatics. Conclusion. The described clinical case indicates that the WNF causative agent circulates in the Kursk region, which justifies the need for blood and cerebrospinal fluid testing in all patients with hyperthermia of unknown origin, combined with neurological symptoms for the WNF virus.

Structural Motifs and Spatial Structures of Helicase (NS3) and RNA-dependent RNA-polymerase (NS5) of a Flavi-like Kindia tick virus (unclassified Flaviviridae)

Kindia tick virus (KITV) is a novel segmented unclassified flavi-like virus of the Flaviviridae family. This virus is associated with ixodes ticks and is potentially pathogenic to humans. The main goal of this work was to search for structural motifs of viral polypeptides and to develop a 3D-structure for viral proteins of the flavi-like KITV. The complete genome sequences for KITV, Zika, dengue, Japanese encephalitis, West Nile and yellow fever viruses were retrieved from GenBank. Bioinformatics analysis was performed using the different software packages. Analysis of the KITV structural proteins showed that they have no analogues among currently known viral proteins. Spatial models of NS3 and NS5 KITV proteins have been obtained. These models had a high level of topological similarity to the tick-borne encephalitis and dengue viral proteins. The methyltransferase and RNA-dependent RNA-polymerase domains were found in the NS5 KITV. The latter was represented by fingers, palm and thumb subdomains, and motifs A-F. The helicase domain and its main structural motifs IVI were identified in NS3 KITV. However, the protease domain typical of NS3 flaviviruses was not detected. The highly conserved amino acid motives were detected in the NS3 and NS5 KITV. Also, eight amino acid substitutions characteristic of KITV/2018/1 and KITV/2018/2 were detected, five of them being localized in alpha-helix and three in loops of nonstructural proteins. Nonstructural proteins of KITV have structural and functional similarities with unsegmented flaviviruses. This confirms their possible evolutionary and taxonomic relationships.

Arthropod-Borne Flaviviruses in Pregnancy.

Flaviviruses are a diverse group of enveloped RNA viruses that cause significant clinical manifestations in the pregnancy and postpartum periods. This review highlights the epidemiology, pathophysiology, clinical features, diagnosis, and prevention of the key arthropod-borne flaviviruses of concern in pregnancy and the neonatal period-Zika, Dengue, Japanese encephalitis, West Nile, and Yellow fever viruses. Increased disease severity during pregnancy, risk of congenital malformations, and manifestations of postnatal infection vary widely amongst this virus family and may be quite marked. Laboratory confirmation of infection is complex, especially due to the reliance on serology for which flavivirus cross-reactivity challenges diagnostic specificity. As such, a thorough clinical history including relevant geographic exposures and prior vaccinations is paramount for accurate diagnosis. Novel vaccines are eagerly anticipated to ameliorate the impact of these flaviviruses, particularly neuroinvasive disease manifestations and congenital infection, with consideration of vaccine safety in pregnant women and children pivotal. Moving forward, the geographical spread of flaviviruses, as for other zoonoses, will be heavily influenced by climate change due to the potential expansion of vector and reservoir host habitats. Ongoing 'One Health' engagement across the human-animal-environment interface is critical to detect and responding to emergent flavivirus epidemics.

West Nile Fever Virus: the current situation in Egypt

West Nile Fever Virus: the current situation in Egypt

Survey of Borrelia burgdorferi sensu lato and West Nile fever virus in wild birds in Bulgaria

Survey of Borrelia burgdorferi sensu lato and West Nile fever virus in wild birds in Bulgaria

A review of vectors, vector borne diseases, vector control and their impact on public health

Mosquitoes are most important insect vectors for human disease transmission. Dengue, yellow fever, chikungunya, and zika are all spread by Aedes mosquitoes in many parts of the world. The primary vector of human malaria transmission is Anopheles. Culex is responsible for the transmission of Japanese encephalitis, lymphatic filariasis and West Nile virus fever. Synthetic pesticides have been successfully utilized in mosquito-control programmes for several decades. However, there are a number of disadvantages to the chemical method. As a result, there has been a rise in concern in the usage of biological agents for mosquito control in recent years. Because of their highly effective mosquitocidal activity, Bacillus sphaericus and Bacillus thuringiensis israelensis have been utilized extensively. While insecticide-based interventions have successfully reduced mosquito populations for a number of years, the reliance on a few number of insecticides has now led to the evolution of resistance. So there is a need to search for novel mosquitocidal bacteria for control the mosquito species. Since soil is one of the world's most diversified environments in which bacteria and fungi are abundant, screening of soil samples for isolation of novel mosquitocidal bacteria is attempted.

Flavivirus NS1 Triggers Tissue-Specific Disassembly of Intercellular Junctions Leading to Barrier Dysfunction and Vascular Leak in a GSK-3β-Dependent Manner.

The flavivirus nonstructural protein 1 (NS1) is secreted from infected cells and contributes to endothelial barrier dysfunction and vascular leak in a tissue-dependent manner. This phenomenon occurs in part via disruption of the endothelial glycocalyx layer (EGL) lining the endothelium. Additionally, we and others have shown that soluble DENV NS1 induces disassembly of intercellular junctions (IJCs), a group of cellular proteins critical for maintaining endothelial homeostasis and regulating vascular permeability; however, the specific mechanisms by which NS1 mediates IJC disruption remain unclear. Here, we investigated the relative contribution of five flavivirus NS1 proteins, from dengue (DENV), Zika (ZIKV), West Nile (WNV), Japanese encephalitis (JEV), and yellow fever (YFV) viruses, to the expression and localization of the intercellular junction proteins β-catenin and VE-cadherin in endothelial cells from human umbilical vein and brain tissues. We found that flavivirus NS1 induced the mislocalization of β-catenin and VE-cadherin in a tissue-dependent manner, reflecting flavivirus disease tropism. Mechanistically, we observed that NS1 treatment of cells triggered internalization of VE-cadherin, likely via clathrin-mediated endocytosis, and phosphorylation of β-catenin, part of a canonical IJC remodeling pathway during breakdown of endothelial barriers that activates glycogen synthase kinase-3β (GSK-3β). Supporting this model, we found that a chemical inhibitor of GSK-3β reduced both NS1-induced permeability of human umbilical vein and brain microvascular endothelial cell monolayers in vitro and vascular leakage in a mouse dorsal intradermal model. These findings provide insight into the molecular mechanisms regulating NS1-mediated endothelial dysfunction and identify GSK-3β as a potential therapeutic target for treatment of vascular leakage during severe dengue disease.

A next-generation (DNA) sequencing (NGS)-based method for identifying the sources of sugar meals in mosquito vectors of West Nile virus in Israel.

Mosquitoes of the genus Culex comprise important vectors of pathogenic arboviruses in our region, including West Nile and Rift Valley Fever viruses. To improve our understanding of the epidemiology and transmission dynamics of arboviruses, we need to study the behavior and ecology of their vectors. The feeding patterns of the vector mosquitoes can be very useful in determining how and where to focus control efforts. For example, determining the preferred blood hosts of the females can assist in the implementation of potentially efficacious strategies for focused control of mosquito females. Determining the plants from which both sexes derive their sugar meals can comprise the initial step towards the formulation of efficient lures for trapping mosquitoes. In the past, plant meal identification was based mainly on chemical detection of fructose and microscopical observations of cellulose particles in mosquito guts. More recent studies have utilized DNA barcoding capable of identifying plant food sources. In the current study, we identify multiple plant species from which large numbers of mosquitoes obtained their sugar meals in one experimental procedure. We employed next generation DNA sequencing to sequence the chloroplast specific plant genes atpB and rbcL.

Tick‐borne encephalitis virus and West‐Nile fever virus as causes of serous meningitis of unknown origin in Kazakhstan

Flaviviruses are a family of viruses that cause many diseases in humans. Their similarity in the antigenic structure causes a cross-reaction, which complicates the precise diagnostic of disease causing agents. Tick-borne encephalitis virus (TBEV), a member of the flavivirus family, is the cause of tick-borne encephalitis (TBE). Worldwide the awareness of this disease is raising, however, in many countries such as the Republic of Kazakhstan (KZ) there is a lack of serological investigation of flaviviruses in humans. In our study, we focused on two TBE endemic regions of KZ (East Kazakhstan Oblast (EKO) and Almaty (AO)) and a region where TBE cases were registered only since 2010 (Akmola Oblast (AkO)). In KZ, up to 400 cases of serous meningitis of unknown origin were registered annually in the period from 2017 to 2019. Our goals were to calculate the prevalence of antibodies against TBEV in patients with suspected meningitis. We collected 179 sera and 130 cerebrospinal fluid (CSF) samples from patients and included a questionnaire with focus on socio-demographical factors and observed tick bites. The human samples were tested with TBEV and West-Nile fever virus (WNFV) IgM and IgG ELISA, by immunofluorescence assay using a flavivirus biochip, and TBEV-specific real-time RT-PCR. We found TBEV and WNFV antibodies in 31 samples by serological and molecular techniques. Seven serum samples out of 31 showed TBEV-specific antibodies, and three serum pairs had WNFV antibodies. Correlating the serological results with the information gained from the questionnaires it becomes apparent that the number of tick bites is a significant factor for a TBEV infection. This result has an impact on diagnostic in KZ and physicians should be aware that both flaviviruses play a role for serous meningitis of unknown origin in KZ.

PREDICTORS FOR THE FORMATION AND FUNCTIONING OF NATURAL FOCALS O F ARBOVIRAL INFECTIONS IN THE TERRITORY OF THE VOLGOGRAD REGION

In the Volgograd region, a large number of febrile patients are registered annually in the summer. Most often, such patients are diagnosed with West Nile fever, however, the clinical manifestations of this disease are similar to the symptoms of other arbovirus fevers, for exampLe, Usutu, Sindbis, Ukuniemi. On the territory of the VoLgograd region, the circuLation of West Nile and Crimea-Congo hemorrhagic fever viruses has been established. In addition, other arboviruses, pathogenic for humans, apparentLy circuLate in the region, the fuLL species composition of which has not yet been estabLished. The existence of a number of arboviruses in the region is due to the possibiLity of a systematic introduction of pathogens by migratory birds, the presence of certain types of reservoirs and carriers here. In different years, antigens of the Sindbis virus, the California serogroup (Inko, Tyaginya virus), Batai, Ukuniemi viruses, and specific antibodies to them were detected in the field material, which indicates the presence of these pathogens in the region. The review provides a potential spectrum of arboviruses pathogenic for humans circulating in the Volgograd Region, as well as its abiotic (climate, bird migration pathways) and biotic factors (carriers, reservoirs).

Current knowledge of vector-borne zoonotic pathogens in Zambia: A clarion call to scaling-up "One Health" research in the wake of emerging and re-emerging infectious diseases.

Although vector-borne zoonotic diseases are a major public health threat globally, they are usually neglected, especially among resource-constrained countries, including those in sub-Saharan Africa. This scoping review examined the current knowledge and identified research gaps of vector-borne zoonotic pathogens in Zambia. Major scientific databases (Web of Science, PubMed, Scopus, Google Scholar, CABI, Scientific Information Database (SID)) were searched for articles describing vector-borne (mosquitoes, ticks, fleas and tsetse flies) zoonotic pathogens in Zambia. Several mosquito-borne arboviruses have been reported including Yellow fever, Ntaya, Mayaro, Dengue, Zika, West Nile, Chikungunya, Sindbis, and Rift Valley fever viruses. Flea-borne zoonotic pathogens reported include Yersinia pestis and Rickettsia felis. Trypanosoma sp. was the only tsetse fly-borne pathogen identified. Further, tick-borne zoonotic pathogens reported included Crimean-Congo Haemorrhagic fever virus, Rickettsia sp., Anaplasma sp., Ehrlichia sp., Borrelia sp., and Coxiella burnetii. This study revealed the presence of many vector-borne zoonotic pathogens circulating in vectors and animals in Zambia. Though reports of human clinical cases were limited, several serological studies provided considerable evidence of zoonotic transmission of vector-borne pathogens in humans. However, the disease burden in humans attributable to vector-borne zoonotic infections could not be ascertained from the available reports and this precludes the formulation of national policies that could help in the control and mitigation of the impact of these diseases in Zambia. Therefore, there is an urgent need to scale-up "One Health" research in emerging and re-emerging infectious diseases to enable the country to prepare for future epidemics, including pandemics.

The Current State of the Vertebrate Animals Populations and their Role in the Persistence of Natural Zoonoses Foci in the Stavropol Territory

The aim of this study was to investigate the current state of vertebrates populations and to determine their role in maintaining natural foci of zoonoses in the Stavropol Territory in 2015–2019. Material and methods. Organ suspensions and blood samples from small mammals and birds were studied using certified diagnostic test-systems for the markers of Crimean hemorrhagic fever, West Nile fever, hemorrhagic fever with renal syndrome, tularemia, and leptospirosis pathogens. The data were statistically processed using Wilson’s method. Results and discussion. Identified have been the main reservoirs of natural-focal infections in the Stavropol Territory at the present stage: birds – for the West Nile fever virus, mammals and birds inhabiting the areas of semi-desert landscape-geographical zone – for Crimean hemorrhagic fever agent. The main natural reservoir of orthohantaviruses in the Stavropol Territory is the common vole Microtus arvalis, which lives in all landscape-geographical zones. The circulation of tularemia and leptospirosis pathogens has been established throughout the whole territory of the region, the small wood mouse Sylvaemus uralensis is of the greatest epizootic significance. Findings indicate the need for further epizootiologic monitoring of Stavropol Territory in order to identify the biocenotic patterns of the pathogens’ existence and the reasons that determine the dynamics of the epizootic process and epidemic manifestations of natural foci. It is advisable to determine the sites of long-term monitoring over the number of carriers and vectors of natural-focal infections and strengthen the epizootiological control over the territory, especially during periods of seasonal activity in carriers and vectors of natural focal infections.