Agent Of Fever Research Articles

Rickettsia rickettsii subsp. californica subsp. nov., the etiologic agent of Pacific Coast tick fever.

The etiologic agent of Pacific Coast tick fever (PCTF), a moderately severe tickborne illness that resembles Rocky Mountain spotted fever (RMSF), was first isolated in 1966 from specimens of Dermacentor occidentalis (the Pacific Coast tick) obtained in California. For several decades, this bacterium was identified ambiguously as the unclassified spotted fever group Rickettsia species 364-D, Rickettsia 364, or Rickettsia philipii. However, none of these epithets satisfied criteria of formal bacterial nomenclature. Data developed from mouse serotyping studies performed 45 years ago, and multi-locus sequence typing several decades later, indicated that this bacterium was similar to, but distinct from isolates of Rickettsia rickettsii, the etiological agent of RMSF. We applied an integrative taxonomic approach, combining phenotypic, ecological, and clinical data with whole genome sequencing of 11 contemporary isolates of this pathogen to identify it as a distinct subspecies of R. rickettsii, and propose the name Rickettsia rickettsii subsp. californica subsp. nov.

Coinfection with Orthohantavirus and Leptospira spp. in Rats Collected from Markets in Indonesia.

Background: Rats are an important reservoir animal for several zoonotic pathogens worldwide, including hantaviruses and Leptospira spp., which are the causative agents of hemorrhagic fever with renal syndrome, hantavirus cardiopulmonary syndrome, and leptospirosis. Although a previous study indicated a high frequency of antihantaviral antibodies in patients with acute fever in Indonesia, circulating hantaviruses and their reservoir animals in the country remain limited. Materials and Methods: The presence of hantavirus in rats captured in the urban area of Bogor, Indonesia, from which Leptospira spp. were isolated using PCR, followed by DNA sequencing. Immunohistochemical analyses were performed to detect hantaviral and leptospiral antigens in rat kidney tissues. Results: Seoul of Orthohantavirus seoulense (SEOV) RNA was detected from 24 of 80 Rattus norvegicus (30%). SEOV and Leptospira coinfection was detected in 10 of 80 rats (12.5%). Immunohistochemistry revealed that hantavirus antigens were positively stained in the interstitial capillaries and cells, whereas Leptospira antigens were stained in the luminal side of the renal tubules. Conclusion: This study revealed a high prevalence of SEOV and SEOV and Leptospira coinfection among rats in the urban areas of Bogor, Indonesia, indicating a potential risk of rat-borne zoonotic diseases in the area.

Molecular detection and phylogenetic analysis of ovine herpesvirus-2 in subclinical infections of cattle and sheep.

Ovine herpesvirus-2 (OvHV-2) is the causative agent of malignant catarrhal fever (MCF), a serious and often fatal disease that affects cattle and other ruminants. This study aimed to investigate the molecular epidemiology and genetic diversity of OvHV-2 strains circulating in sheep and cattle populations in the Jammu and Kashmir region of India. Screening of 150 sheep and 57 cattle blood samples revealed the presence of the OvHV-2 polymerase (pol) gene in 8.6% of sheep, 10% of apparently healthy cattle, and 29.7% of cattle exhibiting MCF-like symptoms. The full-length glycoprotein B (gB) gene (2800bp) and an 875bp internal fragment were successfully amplified, cloned, and sequenced from pol-positive samples. Comparative sequence analysis of the deduced gB amino acid sequences identified seven substitutions at positions 278, 341, 390, 440, 468, 539, and 566 compared to reference strains. Phylogenetic analysis based on the gB nucleotide sequences clustered the OvHV-2 strains from this study within the Indian clade, distinct from strains reported in the UK and US. These findings provide insights into the genetic diversity of OvHV-2 strains circulating in Jammu and Kashmir, with the identified mutations potentially influencing virus-host interactions. Further investigations into the functional implications of these mutations are warranted to understand their role in viral pathogenesis and tropism.

β-enaminoester derivatives exhibit promising in vitro and in silico antiviral potential against Mayaro virus.

Mayaro virus (MAYV) is the causative agent of Mayaro fever, which is characterized mainly by acute fever and long-term severe arthralgia, common manifestations of other arbovirus infections, making the correct diagnosis a challenge. Besides, MAYV infections have been reported in South America, especially in Brazil. However, the lack of vaccines or specific antiviral drugs to control these infections makes the search for new antivirals an urgent need. Herein, we evaluated the antiviral potential of synthetic β-enaminoesters derivatives against MAYV replication and their pharmacokinetic and toxicological (ADMET) properties using in vitro and in silico strategies. For this purpose, Vero cells were infected with MAYV at an MOI of 0.1, treated with compounds (50 µM) for 24h, and virus titers were quantified by plaque reduction assays. Compounds 2b (83.33%) and 2d (77.53%) exhibited the highest activity with inhibition rates of 83.33% and 77.53%, respectively. The most active compounds 2b (EC50 = 18.92 µM; SI > 52.85), and 2d (EC50 = 14.52 µM; SI > 68.87) exhibited higher potency and selectivity than the control drug suramin (EC50 = 38.97 µM; SI > 25.66). Then, we investigated the mechanism of action of the most active compounds. None of the compounds showed virucidal activity, neither inhibited virus adsorption, but compound 2b inhibited virus entry (62.64%). Also, compounds 2b and 2d inhibited some processes involved with the release of new virus particles. Finally, in silico results indicated good ADMET parameters of the most active compounds and reinforced their promising profile as drug candidates against MAYV.

Situational analysis on porcine diseases: general risk assessment and prioritization of epizootic threats to biosecurity systems of pig establishments in the Russian Federation

The results of the situational analysis on porcine diseases in the Russian Federation and the expert assessment prioritizing the list of porcine pathogens significant for the pig industry of the country are presented. The method applied to analyse the expert estimates in the situational analysis allows for rapid assessment and interpretation of the situation with identification of priority diseases to be further addressed. The calculations demonstrated the sufficient degree of agreement among the experts (coefficient of concordance W = 0.61), and Pearson’s chi-squared test statistic χ2 = 51.33 (≥ 21.02607) indicated that the concordance is not random and the results can be used in subsequent studies. The specific features of epizootiology of the agents of African swine fever, classical swine fever, porcine reproductive and respiratory syndrome that can impact the effectiveness of biosecurity systems of pig establishments, as well as further ways for improving biosecurity management measures are discussed. The overall risk for the pig industry in the Russian Federation that is associated with external sources is currently characterized as permanently high, requiring maintaining risk management measures at the pig establishments by both the managerial staff of the establishments and the State Veterinary Service. It is recommended that biosecurity measures against external threats should focus on diseases such as African swine fever (weight λ = 0.52), porcine reproductive and respiratory syndrome (λ = 0.071), classical swine fever (λ = 0.068) and infections considered emerging for the Russian Federation (λ = 0.05) according to the weights based on the expert estimation results. The biosecurity systems of the establishments should equally address other threats significant for the pig industry of the country: swine enzootic pneumonia, porcine pleuropneumonia (Actinobacillus pleuropneumoniae), Aujeszky’s disease, streptococcosis (Streptococcus suis), porcine circovirus infection, foot-and-mouth disease, leptospirosis, transmissible gastroenteritis, cysticercosis (λ = 0.02…0.05). The improvement of the governmental policy for eradication of African swine fever, porcine reproductive and respiratory syndrome, classical swine fever (including the substantial modification of the existing official pig turnover control, zoning, diagnosis and prevention quality, as well as the implementation of biosecurity standards) is the most significant factor, without which the disease eradication perspective is questionable.

Report of an unusual association of Oropouche Fever with Guillain-Barré syndrome in Cuba, 2024.

Oropouche virus is the aetiological agent of Oropouche fever. At present, this is currently considered one of the most important vector-borne diseases in Latin America. On 27 May 2024, the Ministry of Public Health of Cuba reported the first ever outbreak of Oropouche fever. In this report, we describe three human cases of Oropouche virus infection with symptoms and signs of neurological disease and clinical diagnosis of Guillain-Barré Syndrome. This study offers insights regarding that Oropouche virus is a causal agent of neurological disorders and it could be involved in the etiology of the Guillain-Barré Syndrome.

The discovery of novel variants reveals the genetic diversity and potential origin of Seoul orthohantavirus.

Seoul orthohantavirus (SEOV) has been identified as one of the main causative agents of hemorrhagic fever with renal syndrome (HFRS) in China. The virus was found circulating in rodent populations in almost all provinces of the country, reflecting the wide distribution of HFRS. Here, using the direct immunofluorescence assay (DFA) and real-time quantitative reverse transcription PCR (qRT-PCR) approach, we performed screening in 1784 small mammals belonging to 14 species of three orders captured in the main areas of HFRS endemicity in Yunnan province (southwestern China) and identified 37 SEOV-positive rats (36 Rattus norvegicus and 1 Rattus tanezumi). A 3-year surveillance of HFRS epidemics and dynamics of rodent reservoir density and virus prevalence implied a potential correlation between them. The subsequent meta-transcriptomic sequencing and phylogenetic analyses revealed three SEOV variants, among which two are completely novel. The ancestral character state reconstruction (ACSR) analysis based on both novel variants and documented strains from 5 continents demonstrated that SEOV appeared to originate near the southwestern area (Yunnan-Kweichow Plateau) of China, then could spread to other regions and countries by their rodent carriers, resulting in a global distribution today. In summary, these data furthered the understanding regards genetic diversity and the potential origin for SEOV. However, the expanding endemic foci in the province suggest that the virus is spreading over a wider region and is much more diverse than previous depicted, which means that increased sampling is necessary.

Infection Dynamics of Dengue Virus in Caco-2 Cells Depending on Its Differentiation Status.

Dengue virus (DENV), from the Flaviviridae family, is the causative agent of dengue fever and poses a significant global health challenge. The virus primarily affects the vascular system and liver; however, a growing body of evidence suggests its involvement in the gastrointestinal (GI) tract, contributing to clinical symptoms such as abdominal pain, vomiting, and diarrhea. However, the mechanisms underlying DENV infection in the digestive system remain largely unexplored. Prior research has detected viral RNA in the GI tissue of infected animals; however, whether the dengue virus can directly infect human enterocytes remains unclear. In this study, we examine the infectivity of human intestinal cell lines to the dengue virus and their subsequent response. We report that the Caco-2 cell line, a model of human enterocytes, is susceptible to infection and capable of producing viruses. Notably, differentiated Caco-2 cells exhibited a lower infection rate yet a higher level of virus production than their undifferentiated counterparts. These findings suggest that human intestinal cells are a viable target for the dengue virus, potentially elucidating the GI symptoms observed in dengue fever and offering a new perspective on the pathogenetic mechanisms of the virus.

Pathogenicity and transcriptomic resolution in dengue virus serotype 1 infected AGB6 mouse model.

Dengue viruses are the causative agents of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, which are mainly transmitted by Aedes aegypti and Aedes albopictus mosquitoes, and cost billions of dollars annually in patient treatment and mosquito control. Progress in understanding DENV pathogenesis and developing effective treatments has been hampered by the lack of a suitable small pathological animal model. Until now, the candidate vaccine, antibody, and drug for DENV have not been effectively evaluated. Here, we analyzed the pathogenicity of DENV-1 in type Ⅰ and type Ⅱ interferon receptor-deficient mice (AGB6) by intraperitoneal inoculation. Infected mice showed such neurological symptoms as opisthotonus, hunching, ataxia, and paralysis of one or both hind limbs. Viremia can be detected 3 days after infection. It was found that 6.98 × 103 PFU or higher dose induce 100% mortality. To determine the cause of lethality in mice, heart, liver, spleen, lung, kidney, intestinal, and brain tissues were collected from AGB6 mice (at an attack dose of 6.98 × 103 PFU) for RNA quantification, and it was found that the viral load in brain tissues peaked at moribund states (14 dpi) and that the viral loads in the other tissues and organs decreased over time. Significant histopathologic changes were observed in brain tissue (hippocampal region and cerebral cortex). Hematological analysis showed hemorrhage and hemoconcentration in infected mice. DENV-1 can be isolated from the brain tissue of infected mice. Subsequently, brain tissue transcriptome sequencing was performed to assess host response characteristics in infected AGB6 mice. Transcriptional patterns in brain tissue suggest that aberrant expression of pro-inflammatory cytokines induces antiviral responses and tissue damage. Screening of hub genes and their characterization by qPCR and ELISA, it was hypothesized that IL-6 and IFN-γ might be the key factors in dengue virus-induced inflammatory response. Therefore, this study provides an opportunity to decipher certain aspects of dengue pathogenesis further and provides a new platform for drug, antibody, and vaccine testing.

Rapid and specific differentiation of Salmonella enterica serotypes typhi and Paratyphi by multicolor melting curve analysis

Rapid and accurate identification of Salmonella enterica serotypes Typhi and Paratyphi (A, B and C), the causal agents of enteric fever, is critical for timely treatment, case management and evaluation of health policies in low and middle-income countries where the disease still remains a serious public health problem. The present study describes the development of a multiplex assay (EFMAtyping) for simultaneous identification of pathogens causing typhoid and paratyphoid fever in a single reaction by the MeltArray approach, which could be finished within 2.5 h. Seven specific genes were chosen for differentiation of typhoidal and nontyphoidal Salmonella. All gene targets were able to be detected by the EFMAtyping assay, with expected Tm values and without cross-reactivity to other relevant Salmonella serovars. The limit of detection (LOD) for all gene targets was 50 copies per reaction. The LOD reached 102–103 CFU/ml for each pathogen in simulated clinical samples. The largest standard deviation value for mean Tm was below 0.5 °C. This newly developed EFMAtyping assay was further evaluated by testing 551 clinical Salmonella isolates, corroborated in parallel by the traditional Salmonella identification workflow, and serotype prediction was enabled by whole-genome sequencing. Compared to the traditional method, our results exhibited 100% of specificity and greater than 96% of sensitivity with a kappa correlation ranging from 0.96 to 1.00. Thus, the EFMAtyping assay provides a rapid, high throughput, and promising tool for public health laboratories to monitor typhoid and paratyphoid fever.

A case of MERS presenting with acute motor aphasia and tetraparesis and literature review

BackgroundMild encephalopathy wıth reversible splenial lesions (MERS) are a clinical–radiological diagnosis that can be diagnosed with radiological imaging and can be accompanied by impaired consciousness, aphasia, headache, and paralysis. MERS can be divided into two different types based on radiological findings; Involvement of the splenium is seen in type 1, and involvement of the splenium and deep white matter is seen in type 2. MERS Type 2 is very rare in adults. Here, we describe a patient diagnosed with MERS Type 2 and our therapeutic intervention.Case presentationA 22-year-old woman presented with slurred speech, weakness in the extremities and headache that started 14 h ago. The patient had sore throat and fever of 37.6 °C for 2 days, and medical history or family history were unremarkable. Neurological examination revealed that she was conscious, cooperative, with no signs of meningeal irritation. Speech comprehension, naming, and repetition were preserved, motor examination revealed 5/5 left upper extremity strength, 4/5 right upper extremity strength, and 2/5 bilateral lower extremity strength. Diffusion-weighted magnetic resonance imaging (MRI-DWI) revealed bilateral deep white matter and splenium symmetrical diffusion restriction. Blood tests showed high C-reactive protein (CRP) and no leukocytosis. No cells were detected in the cerebrospinal fluid (CSF), protein was 151 mg/dl, glucose was within normal limits. The patient, who developed quadriparesis during follow-up, was started on pulse dose steroids. Neurological examination improved to patient’s baseline at the 12th hour of treatment. In the 72nd hour control MRI-DWI, it was seen that the lesions had regressed. Culture/Polymerase chain reaction (PCR) for bacterial/viral infection agents came back negative. After steroids were given for 5 days, patient was discharged at her baseline.ConclusionsMERS is a rare diagnosis in adults and can be radiologically confused with acute toxic leukoencephalopathy. It can be distinguished clinically by the absence of prior infection, fever, and toxic agent exposure. Although there is no consensus in the literature regarding the treatment, the clinical picture improved rapidly after steroid in our case. Despite being rare, it should be considered in the differential diagnosis of patients with deep white matter lesions in adults.

Tick fever agents in Holstein calves grazing in a tropical region: predisposing factors, impact on milk production, productivity, and role of Rhipicephalus microplus in epidemiology

The present study aimed to evaluate under dairy farm conditions the predisposing factors, impact on milk production and productivity, and the role of Rhipicephalus microplus in the epidemiology of tick fever agents in Holstein calves grazing in a tropical region. A total of 4292 pure female Holsteins were evaluated at a commercial farm. Until April 2020, calves had contact with R. microplus for between 3 and 24 months, while after April 2020, no animal had further contact with ticks. Three times a week the rectal temperature (RT) of all animals was determined, and blood samples were collected for evaluation of tick fever (TF) agents from those that showed RT >39.3 °C. Specific treatment was performed against Anaplasma marginale, Babesia bigemina and Babesia bovis when these TF agents were diagnosed in the blood smears. The number of relapses and treatments for TF agents were sub-classified into scales (1, 2, 3, 4, 5, 6 or 7–10 treatments or relapses, and animals that received blood transfusions). Within each sub-class, the health data of calves during lactation along with productivity data were analyzed. Based in the results, whether an animal received colostrum enriched with powdered colostrum substitute, whether the animal was an embryo transfer calf, and the weight at which each calf was weaned were ascertained as factors leading to more recurrences or treatments against TF agents in post-weaned calves. On average, each recurrence of TF agents that a heifer presented between three and seven months decreased milk production by 213.5 liters in the first lactation. Calves that received a blood transfusion had lower milk production at first lactation; lower weight at first fixed-time artificial insemination (FTAI); older age at first FTAI; older age at first, second, and third calving; and delayed age at third calving by 140 days compared to the farm average. R. microplus was the main agent causing clinical cases of TF on the farm, and 10,770 treatments against TF agents were carried out when calves aged between three and seven months had contact with this tick species (2018 and 2019). When the animals no longer had contact with ticks (2022 and 2023), there were no recurrences or treatments against TF agents despite the presence on the farm of S. calcitrans, which can maintain the transmission of A. marginale to the herd.

Molecular detection of some zoonotic tick-borne pathogens in ticks collected from camels (Camelus dromedarius) as hosts and wild rodents as potential reservoirs.

Ticks and tick-borne pathogens pose a great threat to human and animal health. The present study aimed to determine the prevalence of ticks that infest camels and investigate the presence of tick-borne pathogens in the blood of camels, associated ticks, and surrounding rodents as reservoirs. From 100 inspected camels, from different localities in the Giza governorate, 1000 ixodid ticks were collected; these ticks belonged to three genera: Hyalomma, Amblyomma, and Rhipicephalus. The genus Hyalomma was represented by four species, Hyalomma dromedarii was the most prevalent species (55.4%), followed by Hyalomma excavatum (22%), Hyalomma impeltatum (11.6%) and Hyalomma rufipes (2.8%). The genus Amblyomma was represented by two species, Amblyomma gemma (2.8%) and Amblyomma marmoreum (2.7%), while the genus Rhipicephalus was represented by only one species, Rhipicephalus pulchellus (2.7%). Ticks, camel blood, and rodents (total number 100 brown rats) are screened for tick-borne pathogens (Borrelia burgdorferi, Borrelia miyamotoi, Babesia sp., and Coxiella burnetii) using PCR. Camel blood was found to be infected with Borrelia burgdorferi (66.6%), Borrelia miyamotoi (55%), and Babesia sp. (11.6%). Coxiella burnetii DNA was detected in all the collected ticks but was not detected in the blood of camels or rodents. Borrelia miyamotoi was detected in 12.5% of H. impeltatum, 55% of Camels, and 6% of the rodents, which may indicate a proposed risk of dispersal of B. miyamotoi, the agent of tick-borne relapsing fever.

Mayaro Virus: An Emerging Alphavirus in the Americas.

Mayaro virus (MAYV) is an arbovirus first isolated in Trinidad and Tobago in 1954. MAYV is the causative agent of Mayaro fever, which is characterised by high fever, maculopapular rash, myalgia and arthralgia. The potential for chronic arthralgia is of particular clinical concern. Currently, MAYV outbreaks are restricted to South and Central America, with some cases reported in Africa as well as several imported cases in Europe. However, in recent years, MAYV has become a growing global concern due to its potential to emerge into urban transmission cycles. Challenges faced with diagnostics, as well as a lack of specific antivirals or licensed vaccines further exacerbate the potential global health threat posed by MAYV. In this review, we discuss this emerging arboviral threat with a particular focus on the current treatment and vaccine development efforts. Overall, MAYV remains a neglected arbovirus due to its limited area of transmission. However, with the potential of its urbanisation and expanding circulation, the threat MAYV poses to global health cannot be overlooked. Further research into the improvement of current diagnostics, as well as the development of efficacious antivirals and vaccines will be crucial to help prevent and manage potential MAYV outbreaks.

Discovering Dengue Virus Antibody Using Phage Display Technology

Dengue virus (DENV) is a type of flavivirus transmitted globally by the Aedes aegypti mosquito and is the causal agent of Dengue fever. Due to global warm-ing and rising temperatures worldwide, the rate of exposure to DENV is now reaching unprecedented levels, with over 400 million people getting infected each year. Despite worldwide attention to DENV, there is not currently an effective treatment or vaccine. Here, we focused on developing an antibody for the NS1 protein of the DENV, which enables earlier detection of disease and could further decrease the rate of death. Our study utilized a method more time-saving and cost-effective than the traditional method of extracting antibodies from the blood or B-cells of infected animals that show immu-nity: Phage Display. This technique allowed us to derive monoclonal antibodies (mAbs) from the genome library and select DENV antibodies that bind to antigen proteins. In this study, we used Phage Display to select ninety-six potential antibodies from three phases of panning, which then went through indirect ELISA screening for optical density (OD) confirmation (OD > 1.5). Sixteen of the high optical density antibodies were sent to a DNA sequencing analysis facility where fifteen of them were revealed to be the same 1G1 strain. By understanding how antibodies are discovered using phage display technology, we hope to advance the field with reevaluation of current vaccines and the development of novel ones.

Infection Rates and Characterisation of Rickettsia africae (Rickettsiaceae) Detected in Amblyomma Species from Southern Africa.

Tick-borne rickettsioses are considered among the oldest known vector-borne zoonotic diseases. Among the rickettsiae, Rickettsia africae is the most reported and important in Africa, as it is the aetiological agent of African tick bite fever (ATBF). Studies describing the prevalence of R. africae in southern Africa are fragmented, as they are limited to small geographical areas and focused on Amblyomma hebraeum and Amblyomma variegatum as vectors. Amblyomma spp. ticks were collected in Angola, Mozambique, South Africa, Zambia and Zimbabwe during the sampling period from March 2020 to September 2022. Rickettsia africae was detected using the ompA gene, while characterisation was conducted using omp, ompA, ompB and gltA genes. In total, 7734 Amblyomma spp. ticks were collected and were morphologically and molecularly identified as Amblyomma eburneum, A. hebraeum, Amblyomma pomposum and A. variegatum. Low levels of variability were observed in the phylogenetic analysis of the R. africae concatenated genes. The prevalence of R. africae ranged from 11.7% in South Africa to 35.7% in Zambia. This is one of the largest studies on R. africae prevalence in southern Africa and highlights the need for the inclusion of ATBF as a differential diagnosis when inhabitants and travellers present with flu-like symptoms in the documented countries.

Inactivated rabies-based Lassa fever virus vaccine candidate LASSARAB protects nonhuman primates from lethal disease

Lassa fever virus (LASV), a member of the Arenavirus family, is the etiological agent of Lassa fever, a severe hemorrhagic disease that causes considerable morbidity and mortality in the endemic areas of West Africa. LASV is a rodent-borne CDC Tier One biological threat agent and is on the World Health Organization’s (WHO) Priority Pathogen list. Currently, no FDA-licensed vaccines or specific therapeutics are available. Here, we describe the efficacy of a deactivated rabies virus (RABV)-based vaccine encoding the glycoprotein precursor (GPC) of LASV (LASSARAB). Nonhuman primates (NHPs) were administered a two-dose regimen of LASSARAB or an irrelevant RABV-based vaccine to serve as a negative control. NHPs immunized with LASSARAB developed strong humoral responses to LASV-GPC. Upon challenge, NHPs vaccinated with LASSARAB survived to the study endpoint, whereas NHPs in the control group did not. This study demonstrates that LASSARAB is a worthy candidate for continued development.

A Retrospective Analysis Reveals That the 2021 Outbreaks of African Swine Fever Virus in Ghana Were Caused by Two Distinct Genotypes.

African swine fever virus (ASFV) is the causative agent of African swine fever (ASF), a highly infectious and lethal disease of domesticated swine. Outbreaks of ASF have been mostly restricted to the continent of Africa. The outbreaks that have occurred outside of Africa were controlled by extensive depopulation of the domesticated pig population. However, in 2007, an outbreak occurred in the country of Georgia, where ASFV infected wild pigs and quickly spread across eastern Europe. Since the reintroduction of ASF into Europe, variants of the current pandemic strain, ASFV Georgia 2007/01 (ASFV-G), which is classified as Genotype 2 based on p72 sequencing, have been reported in countries within western Europe, Asia, and the island of Hispaniola. Additionally, isolates collected in 2020 confirmed the presence of variants of ASFV-G in Nigeria. Recently, we reported similar variants of ASFV-G collected from domestic pigs suspected of dying of ASF in Ghana in 2022. Here, we retroactively report, based on full-length sequencing, that similar variants were present in Ghana in 2021. The SNP analysis revealed derivatives of ASFV with distinct genetic markers. Furthermore, we identified three full-length ASFV genomes as Genotype 1, indicating that there were two genotypes circulating in proximity during the 2021 ASF outbreaks in Ghana.

Evaluation of different supportive treatments during packed cell volume replacement in calves naturally infected with tick fever agents.

This study evaluated the effect of different supportive treatments on PCV replacement of dairy calves naturally infected with tick fever (TF) agents, and treated with diminazene and enrofloxacin. Five products were tested as supportive treatments in four experiments. In these experiments, we used Girolando female calves (Gyr × Holstein, genetic ratio of 15/16 and 31/32 Holstein) four to six months old, raised in pasture, naturally infected with TF agents, and infested with R. microplus. Supportive treatment was administered once on day 0 of the study concurrently with specific treatment targeting TF agents. The animals were observed on days 0, 3, and 7. Oral or intravenous administration of a vitamin complex and mineral salts enhanced the increase in PCV and biochemical analytes present in the serum of calves naturally infected with TF agents. No positive effect on PCV values was observed with the administration of (1) invigorating tonic: calcium, casein-peptides and vitamin B12, (2) iron-based stimulant tonic and (3) metabolic tonic: vitamin A, vitamin D, and a fraction of polyunsaturated fatty acids. Supplementation by injection with Type III iron resulted in increased hemoglobin and PCV in treated animals. However, these results did not occur with iron citrate. Therefore, more studies with Type III iron need to be performed. Supportive treatment conferred no advantage in animals with no history of reduced PCV.

Structures of African swine fever virus topoisomerase complex and their implications

African swine fever virus (ASFV) is the causal agent of African swine fever (ASF), which is contagious and highly lethal to domestic pigs and wild boars. The genome of ASFV encodes many proteins important for ASFV life cycle. The functional importance of topoisomerase AsfvTopII has been confirmed by in vivo and in vitro assays, but the structure of AsfvTopII is poorly studied. Here, we report four AsfvTopII complex structures. The ATPase domain structures reveal the detailed basis for ATP binding and hydrolysis, which is shared by AsfvTopII and eukaryotic TopIIs. The DNA-bound structures show that AsfvTopII follows conserved mechanism in G-DNA binding and cleavage. Besides G-DNA, a T-DNA fragment is also captured in one AsfvTopII structure. Mutagenesis and in vitro assays confirm that Pro852 and the T-DNA-binding residue Tyr744 are important for the function of AsfvTopII. Our study not only advances the understanding on the biological function of AsfvTopII, but also provides a solid basis for the development of AsfvTopII-specific inhibitors.