Blood Of Infected Animals Research Articles

Identification of New Single Nucleotide Polymorphisms Potentially Related to Small Ruminant Lentivirus Infection Susceptibility in Goats Based on Data Selected from High-Throughput Sequencing.

Small ruminant lentivirus (SRLV) infections are spread in the flocks of sheep and goats all over the world, causing economic loss. Although only a fraction of infected animals develop disease symptoms, all of them may shed the virus, causing uncontrolled spread of the infection. Antibodies against the virus can be detected in the blood of infected animals and are the main marker of infection. Additionally, in most infected animals, proviral DNA can also be detected, but at different levels. Due to the lack of treatment or vaccines, the most effective strategy to prevent SRLV infections are control programmes introduced by several countries based on the elimination of seropositive individuals from the flock. An alternative approach, which has currently become the rationale, is an identification of host factors which may predispose certain individuals or breeds to resistance or susceptibility to small ruminant lentivirus infection. In our work, attention was paid to goats of the Carpathian breed infected with SRLV. Available RNA-seq results from the blood of 12 goats with a determined level of SRLV proviral load were used to analyse single nucleotide polymorphisms (SNPs) by the variant calling method. Six SNPs within five genes (POU2AF1, BCAT2, TMEM154, PARP14, UBASH3A) were selected for genotyping to determine their association with the level of small ruminant lentivirus proviral DNA in a group of 60 goats. Interestingly, in seronegative individuals, only the TT genotype of the PARP14 gene was observed, while the TMEM154 CC genotype was found only in seropositive goats. Both genes may be considered potential markers for resistance/susceptibility to SRLV infection. In contrast, polymorphisms identified in POU2AF1 and UBASH3A genes seemed to be deleterious for respective protein functions; therefore, these genes are less likely to be recognised as resistance/susceptibility markers of SRLV infection.

Control strategies for emerging infectious diseases: Crimean-Congo hemorrhagic fever management.

Crimean-Congo Hemorrhagic Fever (CCHF) is a significant public health concern transmitted by ticks. This study seeks to thoroughly grasp the epidemiology and transmission patterns of CCHF, which is caused by the CCHF virus (CCHFV), a member of the Nairovirus genus in the Bunyaviridae family. The study investigates the global distribution and endemicity of CCHF, its mortality rates, modes of transmission (including tick bites, contact with infected animal blood, and limited person-to-person transmission), and factors influencing its prevalence across different regions. Genetic diversity within CCHFV and its impact on transmission dynamics are explored, along with efforts to control the disease through tick prevention, antiviral treatment, and the development of vaccines and diagnostics. CCHFV exhibits widespread distribution, particularly in the Middle East, Africa, Asia, and Eastern Europe, with an overall mortality rate of approximately 30% and a case fatality rate ranging from 10% to 40%. Transmission occurs primarily through tick bites and contact with infected animal blood, with limited person-to-person transmission. Livestock workers, slaughterhouse employees, and animal herders in endemic areas are most affected by their frequent interaction with sick animals and ticks. Genetic diversity within CCHFV contributes to variations in transmission dynamics, complicating control efforts. Antiviral ribavirin shows efficacy in treating CCHF infection. This study underscores the importance of further research to understand the enzootic environment, transmission routes, and genetic diversity of CCHFV for effective control measures, including the development of vaccines, treatment options, and diagnostics.

Isolation, molecular characterization, and genetic diversity of recently isolated foot-and-mouth disease virus serotype A in Egypt.

Foot-and-mouth Disease (FMD) is a highly contagious viral disease affecting all hoof-cloven animals. Serotypes A, O and SAT 2 of the foot-and-mouth disease virus (FMDV) are circulating in Egypt. The present study aimed to identify and molecularly characterize the FMDV strains circulating in Northern Egypt during an epidemic that struck the nation in 2022. RNA was extracted from the epithelial specimens, vesicular fluid from affected cattle. The samples were screened using real-time reverse-transcription polymerase chain reaction (RT-PCR) targeting the RNA-dependent RNA polymerase (RdRp) gene. Positive samples underwent individual serotype-specific amplification using primers designed for VP1 of O, A, and SAT 2 serotypes. Subsequently, direct sequencing was performed on the positive samples. The real-time RT-PCR detected positive samples from epithelial and vesicular fluid samples, but not in the blood of infected animals. Out of the 16 samples, seven tested positive for FMDV serotype A. Of these seven positive samples, six were categorized as serotype A-African topotype-G-IV, and these positive samples were isolated in BHK-21 cells, yielding an overt cytopathic effect caused by the virus. In conclusion, it is necessary to sustain continuous surveillance of the evolution of circulating FMDV strains to facilitate the assessment and aid in the selection of vaccine strains for the effective control of FMDV in Egypt.

Crimean-Congo Hemorrhagic Fever Virus: Progress in Vaccine Development.

Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the Nairoviridae family and Bunyavirales order, is transmitted to humans via tick bites or contact with the blood of infected animals. It can cause severe symptoms, including hemorrhagic fever, with a mortality rate between 5 to 30%. CCHFV is classified as a high-priority pathogen by the World Health Organization (WHO) due to its high fatality rate and the absence of effective medical countermeasures. CCHFV is endemic in several regions across the world, including Africa, Europe, the Middle East, and Asia, and has the potential for global spread. The emergence of the disease in new areas, as well as the presence of the tick vector in countries without reported cases, emphasizes the need for preventive measures to be taken. In the past, the lack of a suitable animal model susceptible to CCHFV infection has been a major obstacle in the development of vaccines and treatments. However, recent advances in biotechnology and the availability of suitable animal models have significantly expedited the development of vaccines against CCHF. These advancements have not only contributed to an enhanced understanding of the pathogenesis of CCHF but have also facilitated the evaluation of potential vaccine candidates. This review outlines the immune response to CCHFV and animal models utilized for the study of CCHFV and highlights the progress made in CCHFV vaccine studies. Despite remarkable advancements in vaccine development for CCHFV, it remains crucial to prioritize continued research, collaboration, and investment in this field.

Detection of Monkeypox Disease from Human Skin Images with a Hybrid Deep Learning Model.

Monkeypox, a virus transmitted from animals to humans, is a DNA virus with two distinct genetic lineages in central and eastern Africa. In addition to zootonic transmission through direct contact with the body fluids and blood of infected animals, monkeypox can also be transmitted from person to person through skin lesions and respiratory secretions of an infected person. Various lesions occur on the skin of infected individuals. This study has developed a hybrid artificial intelligence system to detect monkeypox in skin images. An open source image dataset was used for skin images. This dataset has a multi-class structure consisting of chickenpox, measles, monkeypox and normal classes. The data distribution of the classes in the original dataset is unbalanced. Various data augmentation and data preprocessing operations were applied to overcome this imbalance. After these operations, CSPDarkNet, InceptionV4, MnasNet, MobileNetV3, RepVGG, SE-ResNet and Xception, which are state-of-the-art deep learning models, were used for monkeypox detection. In order to improve the classification results obtained in these models, a unique hybrid deep learning model specific to this study was created by using the two highest-performing deep learning models and the long short-term memory (LSTM) model together. In this hybrid artificial intelligence system developed and proposed for monkeypox detection, test accuracy was 87% and Cohen's kappa score was 0.8222.

Crimean-Congo Hemorrhagic Fever (CCHF): An Emerging Disease in Afghanistan

Crimean-Congo hemorrhagic fever (CCHF) seems to be a severe viral infection that is spreading throughout Afghanistan. The first case of CCHF was recorded in March 1998 in Takhar province, located in the country’s north. And since then, multiple new cases and outbreaks have occurred over the years and continue to do so now. CCHF is a viral disease that is transmitted to humans mostly by hard tick bites or direct contact with the blood of infected animals. In Afghanistan, the prevalence of CCHF outbreaks has grown dramatically around Eid-ul-Adha. The primary symptom of this fatal disease is bleeding. There is no cure for CCHF at the moment, but the antiviral drug Ribavirin is used to treat it. This disease presently lacks a commercially accessible vaccine. The disease is recommended to be controlled through preventative measures such as Avoiding insect bites and coming into touch with the blood of a suspicious animal are just a few of the precautions that can be taken.

Development of ELISA-based diagnostic methods for the detection of haemorrhagic septicaemia in animals

Haemorrhagic septicaemia (HS) is an acute infection of cattle and buffaloes caused by the B:2 serotype of Pasteurella multocida. This disease is highly endemic in South Asia. In some peracute cases, there is 100% mortality in infected animals within a few hours of infection. Therefore, timely diagnosis of infection may contribute to its treatment and control to minimize economic losses. The current work reported the development of ELISA-based assays for the detection of anti-P. multocida antibodies and pathogen i.e. P. multocida. Owing to high immunogenicity, membrane proteins (MPs) extracted from local isolates of P. multocida serotype B:2 (PM1, PM2, and PM3) were employed as a potential diagnostic antigen for the development of indirect ELISA (i-ELISA) to detect HS antibodies in animals. MPs extracted from PM1, PM2 and PM3 isolates showed very low heterogeneity; hence MPs from the PM3 isolate were selected for the development of i-ELISA. The concentration of MPs (as coating antigen) of 3.13 μg/well and test sera dilution 1:100 was found to be optimal to perform i-ELISA. The developed method was validated through the detection of anti-P. multocida antibodies in sera of mice, immunized with MPs and formalin killed cells from the three local isolates (PM1, PM2 and PM3) of P. multocida. The significantly higher antibody titer in immunized mice was determined compared to unimmunized mice with the cut off value of 0.139. To detect P. multocida directly from the blood of infected animals, whole cell-based ELISA (cb-ELISA) assay was developed. A better detection signal was observed in the assay where bacterial cells were directly adsorbed on plate wells as compared to poly L-lysine (PLL) assisted attachment at a cell concentration of 106 CFU and 107 CFU respectively. The developed assays can be scaled up and potentially be used for the rapid detection of HS antibodies to gauge the immune status of the animal as well as vaccination efficacy and pathogen detection.

COVID-19 Infection and Prevention. Knowledge, Attitude and Practice Among Jordan population

Monkeypox is a viral infection which was originated from the monkeypox virus in the United Kingdom. It is a double-standard DNA virus belonging to the Orthopoxvirus genus and poxviridae family. It was first found in 1958 in monkeys. The first human case of monkeypox was detected in 1970 and the outbreak in 2022. Monkeypox had been reported in people living in several central and western African countries. Despite being named "monkeypox, “the disease’s source is still unknown. However, African rodents and monkeys might harbor the virus and infect people. It typically starts with rashes, and fever, and may lead to complications if not detected earlier. Its transmission can occur from human to human via skin contact, droplets, and even via the placenta from mother to fetus and also through animals to humans via mucosal lesions and blood of infected animals. Till today there is no secure treatment for monkeypox. The awareness survey was conducted in the period between 29th August 2022 to 30th September 2022 and with the help of google Forms, a self-made questionnaire was created and circulated via social media. The purpose of creating these questions was to see the basic knowledge and to know people's awareness about the monkeypox virus. The software used to record the responses of people is Microsoft excel. The study we conducted was cost-effective and time efficient and illustrated every point through tables and pie charts.

Investigation Around Cases of Crimean-Congo Hemorrhagic Fever—Mauritania, 2022

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic arbovirosis. Humans are infected by tick bites or contact with blood of infected animals. CCHF can be responsible for severe outbreaks due to human-to-human transmission. Our aims were to increase awareness and promote the search for risk factors and disease monitoring to prevent CCHF epidemic, capacity building, appropriate measures to treat patients, and information for the local population. During the outbreak of hemorrhagic fever from February to May 2022, blood samples were collected from 88 patients suspected to be infected with the virus. Diagnosis was established by reverse-transcription polymerase chain reaction (RT-PCR) and/or enzyme-linked immunosorbent assay. CCHF was confirmed by RT-PCR in 7 of 88 (8%) patients. Ticks were found in cattle, sheep, or goats in the areas where the subjects resided, with the exception of 1 CCHF-positive patient in close contact with fresh animal meat. Exposure to potential risk factors was found in all patients. The interval between the onset of symptoms and hospital admission was 2-3 days. All 7 patients were admitted to our hospital and treated promptly by blood transfusion. Two patients died. Mortality is high in patients with the hemorrhagic form of CCHF. Disease prevention is necessary by strengthening vector control, avoiding contact and consumption of organic products from diseased animals, and vaccinating animals in areas where the disease is endemic. Furthermore, it is essential to establish management procedures for patients infected with CCHF virus.

Immunogenicity and safety studies of an inactivated vaccine against Rift Valley fever

Rift Valley fever (RVF) is an emerging transboundary, mosquito-borne, zoonotic viral disease caused by a single serotype of a virus belonging to the Phenuiviridae family (genus Phlebovirus). It is considered an important threat to both agriculture and public health in endemic areas, because the virus, transmitted by different mosquito genera, leads to abortions in susceptible animal hosts especially sheep, goat, cattle, and buffaloes, resulting in severe economic losses. Humans can also acquire the infection, and the major sources are represented by the direct contact with infected animal blood, aerosol, consumption of unpasteurized contaminated milk and the bite of infected mosquitoes. Actually, the EU territory does not seem to be exposed to an imminent risk of RVFV introduction, however, the recent outbreaks in a French overseas department and some cases detected in Turkey, Tunisia and Libya, raised the attention of the EU for a possible risk of introduction of infected vectors. Thus, there is an urgent need to develop new therapeutic and/or preventive drugs, such as vaccines. In our work, we studied the immunogenicity of an inactivated and adjuvanted vaccine produced using a Namibian field strain of RVF virus (RVFV). The vaccine object of this study was formulated with Montanide Pet Gel A, a polymer-based adjuvant that has been previously reported for its promising safety profile and for the capacity to elicit a strong immune response. The produced inactivated vaccine was tested on six sheep and the level of IgM and IgG after the immunization of animals was evaluated by a commercial competitive ELISA, in order to assess the immunogenicity profile of our vaccine and to evaluate its potential use, as an alternative to the attenuated vaccines commercially available, in case of Rift Valley fever epidemic disease on EU territory. Following the administration of the second dose, 35 days after the first one, all animals seroconverted.

Influence of Biological Model on the Formation of the Pathogenic Properties of the West Nile Virus Isolate.

Various biological models are used to isolate West Nile virus, but their role as a selection factor that facilitates selection of isolates with certain properties is usually not evaluated. We compared pathogenic properties of three strains of the West Nile virus obtained from one sample of virus-containing material using different models: WNV Volgograd 900m/18 (on the model of suckling mice), WNV Volgograd 900a/18 (on C6/36 cells) and WNV Volgograd 900v/18 (on Vero cells). WNV Volgograd 900m/18 strain demonstrated virulent (LD50 5×103±0.005×104 PFU, p≤0.05) and neuroinvasive properties, induced viremia and pathomorphological changes in the liver, lymph nodes, and brain of nonlinear white mice. WNV Volgograd 900v/18 strain had similar characteristics except for neuroinvasiveness. WNV Volgograd 900a/18 variant demonstrated minimum virulence (LD50 5×104±0.005×104 PFU, p≤0.05), did not cause neurological symptoms, and was not isolated from the blood of infected animals.

The drug Diprokarb for treatment of idiopathic babesial disease in dogs under the conditions of Russia

Study of efficiency of the drug diprokarb with major active ingredient of imidocarb propionate was conducted. One milliliter of diprokarb contains 120 mg of imidocarb propionate. It was studied under the conditions of Moscow and Moscow Region using an example of spontaneous infestation of dogs with babesial disease. All studies were conducted at veterinary clinics using laboratory studies of the blood of infected animals, as well as the study of ixodic ticks that are the major carriers. Monitoring of physical status of animals was being performed from time of the first appearance of babesial disease clinical signs to the complete disappearance of hematozoons from the blood, as well as products of their vital activity. Studies of the animals, which are not demonstrated evident clinical signs of infection, were also conducted during ixodic ticks’ season of activity. Diprokarb was used as the main drug and the symptomatic therapy was conducted when disease is identified. The drug demonstrated 100 % efficiency when applied at the dose of 6 mg per kg of animal body weight.

Incidence of Bovine Brucellosis in Thatta, Sindh-Pakistan

A study was done to investigate the incidence of Brucella abortus in cattle and buffaloes in Thatta Sindh. A total of n = 360 serum samples were randomly collected from buffaloes and cattle (130 each species). The Rose Bengal Plate Test was used to screen serum samples at first (RBPT). A B. abortus specific indirect enzyme-linked immunosorbent test was performed on RBPT positive samples (i-ELISA). An rPCR was used to investigate the efficacy of detecting Brucella in the blood of infected animals after serum samples were proven to be positive for B. abortus by serology. The effectiveness of an rPCR reported in detecting Brucella at the genus level and later at the species level (B. abortus and B. melitensis) in the serum of sick cattle and buffaloes was investigated. The samples that were verified to be positive via both immunological tests, RBPT and i-ELISA, were submitted to the rPCR for this reason. Initially, rPCR based on the Brucella genus-specific bcsp31 genomic region was utilized. The IS711 genomic region of B. abortus and B. melitensis was discovered using two species-specific rPCRs. By RBPT, 13 serum samples from cattle (10%) and 3 from buffalo (2.31%) were shown to be positive for B. abortus. 8 (6.15%) of the 13 RBPT positive cattle samples also tested positive in i-ELISA, whereas 5 tested negative. The 3 buffalo that tested positive for RBPT then 2 were tested positive for i-ELISA. All 8 seropositive samples had Brucella genus specific rPCR amplification. B. abortus was found in all of the samples using species-specific rPCR.

Molecular detection of 7SL-derived small RNA is a promising alternative for trypanosomosis diagnosis.

Equine trypanosomosis comprises different parasitic diseases caused by protozoa of the subgenus Trypanozoon: Trypanosoma equiperdum (causative agent of dourine), Trypanosoma brucei (nagana) and Trypanosoma evansi (surra). Due to the absence of a vaccine and the lack of efficacy of the few available drugs, these diseases represent a major health and economic problem for international equine trade. Development of affordable, sensitive and specific diagnostic tests is therefore crucial to ensure the control of these diseases. Recently, it has been shown that a small RNA derived from the 7SL gene (7SL-sRNA) is produced in high concentrations in sera of cattle infected with Trypanosoma congolense, Trypanosoma vivax and Trypanosoma brucei. Our objective was to determine whether 7SL-sRNA could serve as a marker of active infection in equids experimentally infected with Trypanosoma equiperdum by analysing the sensitivity, specificity and stability of the 7SL-sRNA. Using a two-step RT-qPCR, we were able to detect the presence of 7SL-sRNA between 2 and 7days post-infection, whereas seroconversion was detected by complement fixation test between 5 and 14days post-infection. There was a rapid loss of 7SL-sRNA signal from the blood of infected animals one day post-trypanocide treatment. The 7SL-sRNA RT-qPCR allowed an early detection of a treatment failure revealed by glucocorticoid-induced immunosuppression. In addition, the 7SL-sRNA remains detectable in positive sera after 7days of storage at either 4°C, room temperature or 30°C, suggesting that there is no need to refrigerate serum samples before analysis. Our findings demonstrate continual detection of 7SL-sRNA over an extended period of experimental infection, with signals detected more than six weeks after inoculation. The detection of a strong and consistent 7SL-sRNA signal even during subpatent parasitemia and the early detection of treatment failure highlight the very promising nature of this new diagnostic method.

Identification of clinically approved small molecules that inhibit growth and affect transcript levels of developmentally regulated genes in the African trypanosome.

Trypanosoma brucei are unicellular parasites endemic to Sub-Saharan Africa that cause fatal disease in humans and animals. Infection with these parasites is caused by the bite of the tsetse fly vector, and parasites living extracellularly in the blood of infected animals evade the host immune system through antigenic variation. Existing drugs for Human and Animal African Trypanosomiasis are difficult to administer and can have serious side effects. Resistance to some drugs is also increasing, creating an urgent need for alternative trypanosomiasis therapeutics. We screened a library of 1,585 U.S. or foreign-approved drugs and identified 154 compounds that inhibit trypanosome growth. As all of these compounds have already undergone testing for human toxicity, they represent good candidates for repurposing as trypanosome therapeutics. In addition to identifying drugs that inhibit trypanosome growth, we wished to identify small molecules that can induce bloodstream form parasites to differentiate into forms adapted for the insect vector. These insect stage parasites lack the immune evasion mechanisms prevalent in bloodstream forms, making them vulnerable to the host immune system. To identify drugs that increase transcript levels of an invariant, insect-stage specific surface protein called procyclin, we engineered bloodstream reporter parasites that express Green Fluorescent Protein (GFP) following induction or stabilization of the procyclin transcript. Using these bloodstream reporter strains in combination with automated flow cytometry, we identified eflornithine, spironolactone, and phenothiazine as small molecules that increase abundance of procyclin transcript. Both eflornithine and spironolactone also affect transcript levels for a subset of differentiation associated genes. While we failed to identify compounds that increase levels of procyclin protein on the cell surface, this study is proof of principle that these fluorescent reporter parasites represent a useful tool for future small molecule or genetic screens aimed at identifying molecules or processes that initiate remodeling of the parasite surface during life cycle stage transitions.

The expression of cytokines in the milk somatic cells, blood leukocytes and serum of goats infected with small ruminant lentivirus

BackgroundThe present study aimed to determine the expression of cytokines, which is associated with the immunological response of dairy goats against small ruminant lentivirus (SRLV). The study was conducted on 26 dairy goats in their second to sixth lactation, which were divided by breed and parity into two groups: SRLV naturally infected (N = 13) and non-infected (N = 13) animals. All goats in the study were asymptomatic. The milk and blood samples, which served as studied material were taken on days 7, 30, 120 and 240 of the lactation. The gene and protein expression of several cytokines was studied using Real-Time PCR and ELISA methods.ResultsINF-β and INF-γ expression was down-regulated in the milk somatic cells (MSC) of SRLV-infected goats. However, an increased concentration of INF-β was observed in the MSC in SRLV-infected goats, while INF-γ expression was not observed in both SRLV-infected and non-infected animals The SRLV-infected goats also displayed decreased expression of IL-1α, IL-1β, IL-6 and INF-γ genes in the blood leukocytes,with IL-1α, IL-1β and IL-6 protein levels also being decreased in the sera. TNF-α was the only gene that demonstrated increased expression in both the MSC and the blood of infected animals; however, no such overexpression was observed at the protein level.ConclusionsSRLV probably influences the immune system of infected animals by deregulating of the expression of cytokines. Further, epigenetic studies may clarify the mechanisms by which SRLV regulates the gene and protein expression of the host.

Host nutritional status affects alphavirus virulence, transmission, and evolution.

Malnourishment, specifically overweight/obesity and undernourishment, affects more than 2.5 billion people worldwide, with the number affected ever-increasing. Concurrently, emerging viral diseases, particularly those that are mosquito-borne, have spread dramatically in the past several decades, culminating in outbreaks of several viruses worldwide. Both forms of malnourishment are known to lead to an aberrant immune response, which can worsen disease outcomes and reduce vaccination efficacy for viral pathogens such as influenza and measles. Given the increasing rates of malnutrition and spread of arthropod-borne viruses (arboviruses), there is an urgent need to understand the role of host nutrition on the infection, virulence, and transmission of these viruses. To address this gap in knowledge, we infected lean, obese, and undernourished mice with arthritogenic arboviruses from the genus Alphavirus and assessed morbidity, virus replication, transmission, and evolution. Obesity and undernourishment did not consistently influence virus replication in the blood of infected animals except for reductions in virus in obese mice late in infection. However, morbidity was increased in obese mice under all conditions. Using Mayaro virus (MAYV) as a model arthritogenic alphavirus, we determined that both obese and undernourished mice transmit virus less efficiently to mosquitoes than control (lean) mice. In addition, viral genetic diversity and replicative fitness were reduced in virus isolated from obese compared to lean controls. Taken together, nutrition appears to alter the course of alphavirus infection and should be considered as a critical environmental factor during outbreaks.

Derivation of simian tropic HIV-1 infectious clone reveals virus adaptation to a new host

To replicate in a new host, lentiviruses must adapt to exploit required host factors and evade species-specific antiviral proteins. Understanding how host protein variation drives lentivirus adaptation allowed us to expand the host range of HIV-1 to pigtail macaques. We have previously derived a viral swarm (in the blood of infected animals) that can cause AIDS in this new host. To further exploit this reagent, we generated infectious molecular clones (IMCs) from the viral swarm. We identified clones with high replicative capacity in pigtail peripheral blood mononuclear cells (PBMC) in vitro and used in vivo replication to select an individual IMC, named stHIV-A19 (for simian tropic HIV-1 clone A19), which recapitulated the phenotype obtained with the viral swarm. Adaptation of HIV-1 in macaques led to the acquisition of amino acid changes in viral proteins, such as capsid (CA), that are rarely seen in HIV-1-infected humans. Using stHIV-A19, we show that these CA changes confer a partial resistance to the host cell inhibitor Mx2 from pigtail macaques, but that complete resistance is associated with a fitness defect. Adaptation of HIV-1 to a new host will lead to a more accurate animal model and a better understanding of virus-host interactions.

Use of magnetically disentangled thiolated carbon nanotubes as a label-free impedimetric genosensor for detecting canine Leishmania spp. infection

We discuss the development of a thiolated carbon nanotube (ThNT) transducer for femtomolar detection of Leishmania spp. (CL) DNA based on the use of electrical impedance spectroscopy. Aminated short single strands probes of the chosen DNA target were covalently linked to carboxyl-functionalized ThNTs, anchored upon ultrathin Au films. The genosensors exhibit a less resistive behavior when an external magnetic field was applied to forcefully disentangle the ThNTs during their covalent immobilization, than when immobilized in their natural randomly oriented form. Under disentangled conditions the sensors presented a linear detection of parasite DNA in the 0.1 to 98.3 fg/μL range. The lower limit corresponds to a CL DNA concentration of 15 fM in canine genomic samples extracted directly from the blood of infected animals. The covalent immobilization of the ThNTs at the electrode surface reduces their tendency to peeling off. As a result, one could recycle the sensors after each experiment by rinsing them with hot water and use them for at least 5 successive times, with a relative standard deviation lower than 5%. Since no amplification of the target DNA is required, we suggest that use of these genosensors can represent a simple and yet accurate approach for the fast-molecular diagnosis of canine leishmaniasis.

Virulence of Pigmented Serratia marcescens Strain SM6 and its Nalidixic Acid-Resistant Derivative in White Outbred Mice

Human opportunistic pathogen Serratia marcescens is a bacterium with broad host range representing a growing problem for public health. Little is known about virulence factors used by S. marcescens to colonize the host. We used white outbred mice to study virulence of S. marcescens wild type strain SM6 and its nalidixic acid-resistant derivative during intraperitoneal infection. We showed that both strains were lethal for mice at 107–108 CFU and death occurred within 24–48 h post infection. No mortality was noticed at 106 CFU. Bacteria were isolated from hearts, lungs, kidneys, livers, spleens, intestines, and blood of infected animals. Resistance to nalidixic acid did not affect virulence of S. marcescens. Thus, this strain can be used in the future virulence studies to simplify tracking and recovery of S. marcescens from infected tissue.