Serological Evidence Of Infection Research Articles

Acute Deep Venous Thrombosis Associated with Acute Brucellosis: A Case Report

Brucellosis continues to be one of the most widespread zoonoses worldwide. Human brucellosis is a multisystem disease that may present with a broad spectrum of clinical manifestations, but it may also be asymptomatic with only serological evidence of infection. In this paper, a case report is presented of deep venous thrombosis (DVT) developing after a diagnosis of acute brucellosis in a young slaughterhouse worker. A 26-year-old man was diagnosed with DVT which had presented with the complaints of weakness and fever and a one-week history of pain and swelling in the right leg. Ultrasound revealed that the right femoral and popliteal veins were occluded with thrombi. Brucella was diagnosed using Rose-Bengal, tube agglutination, the Brucellacapt test and an enzyme-linked immunoassay using anti-Brucella abortus IgM/G antibody detection at another institution. Although rare, some infectious agents may cause vascular pathologies. These conditions may be life-threatening. Thus, it should be kept in mind that vascular complications may occur during infectious disease and patients should be monitored. Additionally, patients presenting with symptoms of DVT or similar vascular pathologies should be assessed for infectious agents, particularly Brucella and Salmonella, as well as other risk factors.

Seroprevalence of major blood-borne infections among blood donors in Kano, Nigeria

To examine the seroprevalence of common blood infections among blood donors, which remains a major concern in transfusion medicine in Nigeria. Blood transfusion is one of the known therapeutic interventions that cut across a number of clinical disciplines. Materials and methods: The seroprevalences of human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B surface antigen (HBsAg), and syphilis among 280 blood donors at the Murtala Mohammed Specialist Hospital (MMSH) were determined. The seroprevalences of the pathogens were determined with regard to age, sex, donor category, and occurrence of association pathogens. Between June and December 2008, 276 males (98.6%) and 4 females (1.4%), with an age range of 18-54 years, donated blood. Results: Tests showed that 54 (19.3%) donors had serological evidence of infection with at least one pathogen, while 8 (2.9%) had multiple infections. The seroprevalences of syphilis, HBsAg, HCV, and HIV were found to be 7.5%, 11.1%, 1.8%, and 1.4%, respectively, at the MMSH in Kano. The age group of 28-37 years had the highest rates of syphilis (8.7%), HBsAg (15.5%), and HIV (2.9%), while the age group of 18-27 years had the highest prevalence of HCV (2.5%). Conclusion: The high (19.3%) seroprevalence of transfusion-transmissible infections in blood donated at the MMSH calls for comprehensive screening of blood donors for HBsAg, HCV, HIV, and syphilis using sensitive techniques and strict selection criteria of donors.

Metagenomic Analysis of Fever, Thrombocytopenia and Leukopenia Syndrome (FTLS) in Henan Province, China: Discovery of a New Bunyavirus

Since 2007, many cases of fever, thrombocytopenia and leukopenia syndrome (FTLS) have emerged in Henan Province, China. Patient reports of tick bites suggested that infection could contribute to FTLS. Many tick-transmitted microbial pathogens were tested for by PCR/RT-PCR and/or indirect immunofluorescence assay (IFA). However, only 8% (24/285) of samples collected from 2007 to 2010 tested positive for human granulocytic anaplasmosis (HGA), suggesting that other pathogens could be involved. Here, we used an unbiased metagenomic approach to screen and survey for microbes possibly associated with FTLS. BLASTx analysis of deduced protein sequences revealed that a novel bunyavirus (36% identity to Tehran virus, accession: HQ412604) was present only in sera from FTLS patients. A phylogenetic analysis further showed that, although closely related to Uukuniemi virus of the Phlebovirus genus, this virus was distinct. The candidate virus was examined for association with FTLS among samples collected from Henan province during 2007–2010. RT-PCR, viral cultures, and a seroepidemiologic survey were undertaken. RT-PCR results showed that 223 of 285 (78.24%) acute-phase serum samples contained viral RNA. Of 95 patients for whom paired acute and convalescent sera were available, 73 had serologic evidence of infection, with 52 seroconversions and 21 exhibiting a 4-fold increase in antibody titer to the virus. The new virus was isolated from patient acute-phase serum samples and named Henan Fever Virus (HNF virus). Whole-genome sequencing confirmed that the virus was a novel bunyavirus with genetic similarity to known bunyaviruses, and was most closely related to the Uukuniemi virus (34%, 24%, and 29% of maximum identity, respectively, for segment L, M, S at maximum query coverage). After the release of the GenBank sequences of SFTSV, we found that they were nearly identical (>99% identity). These results show that the novel bunyavirus (HNF virus) is strongly correlated with FTLS.

Haiti in the Context of the Current Global Cholera Pandemic

Haiti in the Context of the Current Global Cholera Pandemic

Serologic Survey of the Pandemic H1N1 2009 Virus in Guangdong Province, China: A Cross Sectional Study

BackgroundRelying on surveillance of clinical cases limits the ability to understand the full impact and severity of an epidemic, which urges a deep insight into the serological evidence of infection and transmission feature of pandemic H1N1 2009 (pH1N1) virus in Guangdong province.MethodsIn this cross-sectional serological survey, serum samples were collected by multi-stage stratified random sampling in Jan 2010. Antibody titers were measured by hemagglutination inhibition (HI) assay. Age-specific and region-specific prevalence were calculated based on the results of HI assay (positive, HI titer≥1∶40).ResultsA total of 4,319 serum samples had been collected from subjects without vaccination with pH1N1 vaccine. The seroprevalence was 22.82% (985/4,319). By contrast, there was a marked spatial heterogeneity in prevalence. The seroprevalence was 27.3% in large city, 21.4% in medium cities, higher than that of 20.2% in rural areas. The seroprevalence was highest in 11–20 age group (32.8%), however, in those above 60 years of age group, which was 12.6%, lower than other age groups. On the other hand, antibody titers to pH1N1 virus were highest in school children, which were followed by a gradual decrease in adult. However, in the elderly groups from cities, especially from large city, the antibody titer to pH1N1 increased significantly and reached a much higher level.ConclusionOur results showed that the prevalence for pH1N1 was correlated with age and population density. Preexisting antibody may have protected the very old from pH1N1 infection, while original antigenic sin and immunosenescence may have contributed to greater severity once infected. These should be considered when studying the pathogenesis and transmission of influenza virus and formulating strategies on vaccination and treatment.

Factors associated with infection by 2009 pandemic H1N1 influenza virus during different phases of the epidemic

The focus of this study was to ascertain the factors associated with 2009 pandemic influenza H1N1 (pH1N1) infection during different phases of the epidemic. In central Taiwan, 306 persons from households with schoolchildren were followed sequentially and serum samples were taken at three sampling time-points starting in the fall of 2008, shortly after influenza vaccination. Participants who seroconverted between two consecutive blood samplings were considered as having serological evidence of infection. A generalized estimation equation (GEE) with a logistic link to account for household correlations was applied to identify factors associated with pH1N1 infections during the pre-epidemic (April-June) and epidemic (September-October) periods. The results showed that receiving an inactivated seasonal influenza vaccine (ISIV) and having a hemagglutination inhibition assay (HI) titer of 40 or higher resulted in a significantly lower likelihood of pH1N1 infection during the pre-epidemic period only, for both children and adults (adjusted odds ratio (OR) 0.3, 95% confidence interval (CI) 0.12-0.9). Having a previous infection by pH1N1 with a baseline titer of 20 or higher resulted in a significantly lower likelihood of infection by pH1N1 during the epidemic period (adjusted OR 0.06, 95% CI 0.02-0.16). Our results provide the first serological evidence to suggest a protection effect from receiving an ISIV against pH1N1 infection only when the HI titer reaches 40 or higher during the pre-epidemic period. This study gives an important insight into the control and intervention measures required for preventing infections during future influenza epidemics.

Genetic and Immunological Factors Involved in Natural Resistance to HIV-1 Infection

Infection with Human immunodeficiency virus type-1 (HIV-1) induces severe alterations of the immune system leading to an increased susceptibility to opportunistic infections and malignancies. However, exposure to the virus does not always results in infection. Indeed, there exist individuals who have been repeatedly exposed to HIV-1 but do not exhibit clinical or serological evidence of infection, known as exposed seronegative individuals. Many studies have focused on the different mechanisms involved in natural resistance to HIV-1 infection, and have reported several factors associated with this phenomenon, including the presence of genetic polymorphisms in the viral coreceptors, innate and adaptive immune cells with particular phenotypic and functional features, and molecules such as antibodies and soluble factors that play an important role in defense against infection by HIV-1. The study of these factors could be the key for controlling this viral infection. This review summarizes the main mechanisms involved in resistance to HIV-1 infection.

Progress in Infectious Disease and Immunology

INFECTIOUS DISEASES ARE COMMONLY ENCOUNTERED IN VIRtually all areas of health care, can represent potential major threats to communities and public health, and account for substantial morbidity and mortality. On a global level, infectious diseases such as malaria and tuberculosis remain leading causes of death. Among hospitalized patients, infectious complications such as central line– associated bloodstream infections, ventilator-associated pneumonia, and surgical site infections continue to be important causes of morbidity and increased length of stay. Illness related to infectious diseases also accounts for significant numbers of office and emergency department visits as well as substantial heath care costs and leads to losses in productivity among workers. In addition, the management of infectious diseases continues to be challenging, with major concerns about the emergence of multidrug-resistant pathogens and a significant decline in the production of new antimicrobial agents from both research and industry sources. Immunologic disorders also are increasingly prevalent, with improved detection of common immunologic and allergic conditions; expanded numbers of patients living longer with immune-suppressing disorders such as human immunodeficiency virus (HIV) infection and some cancers; and increasing numbers of patients receiving immunemodulating and immunosuppressing medications, such as patients with connective tissue disorders and recipients of organ, tissue, and stem cell transplants. Many of these disorders can take a devastating toll on physical functioning, quality of life, and emotional well-being. This theme issue of JAMA, devoted to infectious diseases and immunology, includes research reports and other scholarly articles that provide new information to help inform clinicians about these issues. Three clinical trials in this issue provide data on approaches to treatment and prevention of 3 relatively common infectious disease processes. In a noninferiority trial of tuberculosis treatment conducted among 1585 adults with newly diagnosed tuberculosis at 11 sites in Africa, Asia, and Latin America, Lienhardt and colleagues demonstrated that compared with a regimen of 4 separately administered medications, a fixed-dose 4-drug combination formulation satisfied noninferiority criteria in 2 of 3 analyses. The authors suggest that even though the results do not demonstrate full noninferiority, the potential advantages related to administration and adherence using the fixed-dose combination over separate drug formulations may make this a preferred approach, particularly in resource-poor settings. In another noninferiority clinical trial evaluating alternative dosing regimens for human papillomavirus (HPV) vaccination among 903 adolescent girls in Vietnam, Neuzil and colleagues found that the use of 2 alternative HPV vaccine dosing schedules (at 0, 3, and 9 months and at 0, 6, and 12 months) compared with the standard vaccine schedule (0, 2, and 6 months) did not result in inferior antibody concentrations, although the yearly vaccination schedule (0, 12, and 24 months) did not meet prespecified noninferiority criteria. The study, however, only addressed immunogenicity and reactivity and does not provide information on the efficacy of these dosage regimens for preventing cervical cancer. In a clinical trial of hepatitis B vaccination conducted at 33 centers in France, Launay and colleagues compared the safety and immunogenicity of a 4-intramuscular doubledose regimen (40 μg at weeks 0, 4, 8, and 24) and a 4-intradermal low-dose regimen (4 μg at weeks 0, 4, 8, and 24) vs the standard regimen (20 μg at weeks 0, 4, and 24) of recombinant hepatitis B virus (HBV) vaccine among 396 HIV1–infected adults with CD4 cell counts greater than 200/μL and who were HBV seronegative. The investigators report that both the 4 intramuscular double-dose regimen and the 4 intradermal low-dose regimen improved serological response compared with the standard HBV vaccine regimen. The findings also suggest that intradermal administration of this regimen may be more efficient than the standard intramuscular administration in achieving immunogenicity. Three observational studies in this issue report novel information on 3 clinically important and prevalent conditions. In a study of 498 immunocompetent adults with serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Tronstein and colleagues measured the rate of viral shedding using polymerase chain reaction (PCR) detection of HSV-2 DNA from self-collected genital swabs obtained on consecutive days. Among 410 symptomatic persons with a history of genital lesions, HSV was detected on

Serological evidence of vertical transmission of JC and BK polyomaviruses in humans

Vertical transmission of JC virus and BK virus has been investigated by few authors, with conflicting results. We performed a combined serological and genomic study of 19 unselected pregnant women and their newborns. Blood and urine samples were collected during each gestational trimester from the pregnant women. Umbilical cord blood, peripheral blood, urine and nasopharyngeal secretion samples were taken from newborns at delivery and after 1 week and 1 month of life. Polyomavirus DNA was detected by nested PCR. Polyomavirus IgG-, IgM- and IgA-specific antibodies were measured in maternal and newborn serum samples using a virus-like-particle-based ELISA method. BKV and JCV DNA were detected in urine from 4 (21 %) and 5 (26 %) women, respectively. BKV and JCV seroprevalences in the pregnant women were 84 % and 42 %, respectively. Using a rise in the IgG level or the transient appearance of an IgA or IgM response as evidence of infection in the newborn, we detected BKV and JCV infections in four (21 %) and three (16 %) newborns, respectively. Three infants had serological evidence of infection with both BKV and JCV. In two of the four possible BKV-infected newborns, the mothers seroconverted during pregnancy, while another mother was viruric and IgA seropositive. The mother of one of the three possible JCV-infected newborns was viruric and IgA seropositive; another mother was viruric. These results suggest JC virus and BK virus can be transmitted from mother to newborn during pregnancy or soon after birth.

A Serosurvey of Crimean‐Congo Haemorrhagic Fever Virus in Dairy Cattle in Iran

A seroepidemiological survey to determine the prevalence of Crimean-Congo haemorrhagic fever (CCHF) virus among dairy cattle in Iran was carried out during 2006 and 2008. Blood samples were collected from 876 animals in five different provinces of the country. Sera were tested by a sandwich enzyme-linked immunosorbent assay (ELISA) for quantitative determination of antibodies to CCHF virus. Serological evidence of infection was noted in 52 (5.9%) of 876 dairy cattle. Antibody prevalence increased with age; 78.8% seroprevalence in cattle older than 3 years versus 21.2% in animals less than 2 years old. There was a difference between provinces representing north-east (11.7%) and east (2%) of Iran.

Genetic determinants of hepatitis B vaccine response

Hepatitis B is a major public health problem. Approximately one-third of the world’s population has serological evidence of infection with hepatitis B virus (HBV). 350 million of these are carriers who have chronic HBV infection, and about a million of these carriers die each year from chronic liver disease, including cirrhosis and liver cancer. Fortunately, HBV is a vaccine preventable disease, and the increasing adoption of this vaccine has led to dramatic reductions in the morbidity and mortality caused by this virus. However, as much as 10% of the population fails to mount a protective immune response after vaccination. Twin and other epidemiological studies have demonstrated an unusually high heritability to this trait, which suggests a high likelihood of identifying genetic variation influencing HBV vaccine response. In search of such variation, we performed a two stage Genome Wide Association Scan (GWAS) in participants of a vaccine efficacy trial from Batam, Indonesia. In Stage 1, we used the fixed content Illumina Infinium 550K SNP BeadChip to genotype 2000 vaccinees. Tests of association were performed to identify 7,000 SNPs to carry forward to a second stage of 2,300 vaccinees. Several independent regions attained genome-wide significance, including the HLA-DR and HLA-DP regions. Additional details on the study design and results will be discussed in the presentation.

Transmission of influenza A viruses between pigs and people, Iowa, 2002–2004

Triple-reassortant (tr) viruses of human, avian, and swine origin, including H1N1, H1N2, and H3N2 subtypes, emerged in North American swine herds in 1998 and have become predominant. While sporadic human infections with classical influenza A (H1N1) and with tr-swine influenza viruses have been reported, relatively few have been documented in occupationally exposed swine workers (SW). We conducted a 2-year (2002-2004) prospective cohort study of transmission of influenza viruses between pigs and SW from a single pork production company in Iowa. Respiratory samples were collected and tested for influenza viruses from SW and from pigs under their care through surveillance for influenza-like illnesses (ILI). Serial blood samples from study participants were tested by hemagglutination inhibition (HI) for antibody seroconversion against human and swine influenza viruses (SIV), and antibody seroprevalence was compared to age-matched urban Iowa blood donors. During the first year, 15 of 88 SW had ILI and were sampled; all were culture-negative for influenza. During the second year, 11 of 76 SW had ILI and were sampled; one was culture-positive for a human seasonal H3N2 virus. Among 20 swine herd ILI outbreaks sampled, influenza A virus was detected by rRT-PCR from 17 with 11 trH1N1 and five trH3N2 virus isolates cultured. During both years, HI geometric mean titers were significantly higher among SW compared to blood donor controls for three SIV: classical swine Sw/WI/238/97 (H1N1), tr Sw/IN/9K035/99 (H1N2), and trSw/IA/H02NJ56371/02 (H1N1)] (P < 0·0001). SW had serologic evidence for infection with both swine and human influenza viruses and were exposed to diverse influenza virus strains circulating in pigs. Influenza virus surveillance among pigs and SW should be encouraged to better understand cross-species transmission and diversity of influenza viruses at the human-swine interface.

Persistent infection by HCV and EBV in peripheral blood mononuclear cells and risk of non-Hodgkin's lymphoma

Hepatitis C virus (HCV) and Epstein–Barr virus (EBV) have been repeatedly associated with risk of non-Hodgkin's lymphoma (NHL) in studies focusing on serological evidence of infection. We investigated NHL risk in association with detection of HCV-RNA or EBV-DNA in the peripheral blood mononuclear cells (PBMC). The study involved 91 NHL cases and 182 controls nested in the Italian branch of the EPIC (European Prospective Investigation of Cancer and nutrition) cohort, which obtained blood samples from 47,749 healthy volunteers between 1993 and 1998 in 5 Italian cities. NHL cases were identified until June 2005 through linkage with records of the Cancer, Mortality, and Hospital Discharge Registries. For all study subjects, we performed viral genome analyses on DNA and RNA extracted from buffy-coats and analysed EBV and HCV antibodies. The odds ratios (ORs) of NHL were 1.2 (95% confidence intervals: 0.4–3.8; 5 exposed cases) for PBMC HCV infection and 1.2 (0.7–2.3; 24 exposed cases) for PBMC EBV infection. Similar OR estimates were found for detection of EBV and HCV antibodies. These null results, although based on a relatively small sample size, suggest that persistent EBV and HCV infection in the PBMC is not a stronger predictor of NHL risk than serological evidence of infection.

Funcionamiento cognitivo antes del inicio de la psicosis: papel de la exposición fetal al virus de la gripe verificada con exámenes serológicos

Background Previous studies have linked prenatal influenza exposure to increased risk of schizophrenia; however, no study has examined the neurodevelopmental sequelae of this prenatal insult before the onset of psychotic symptoms using serological evidence of infection. This study sought to examine the contribution of prenatal influenza A and B exposure to cognitive performance among children who developed psychoses in adulthood versus nonpsychiatric control children. Methods Subjects were 111 cases (70 with schizophrenia and 41 with affective psychoses) and 333 matched control subjects followed from gestation until age 7 through the Collaborative Perinatal Project. The Wechsler Intelligence Scale for Children (age 7) was administered and adult psychiatric morbidity was assessed by medical records review and confirmed by a validation study. Assays were conducted from archived prenatal maternal sera collected at birth, and influenza infection was determined by immunoglobulin G (IgG) antibody titers 75th percentile. Results Significant decreases in verbal IQ and the information subtest, as well as similar nonsignificant reductions in full scale IQ scores and vocabulary, comprehension, digit span, and picture arrangement subtests were found among cases who were prenatally exposed to influenza B versus cases who were not exposed. Fetal exposure to influenza B did not lead to any significant differences in cognitive performance among control children. Conclusions Cumulatively, these findings suggest that a genetic and/or an environmental factor associated with psychosis rendered the fetal brain particularly vulnerable to the effects of influenza B, leading to poorer cognitive performance even before symptom onset.

Seroprevalence of HIV, HBV, HCV and syphilis infections among blood donors at Gondar University Teaching Hospital, Northwest Ethiopia: declining trends over a period of five years

BackgroundTransfusion-transmissible infectious agents such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis are among the greatest threats to blood safety for the recipient. This study aimed to determine the seroprevalence, risk factors and trends of HIV, HBV, HCV and syphilis infections among blood donors over a period of five years at Gondar University Teaching Hospital, Northwest Ethiopia.MethodsA retrospective analysis of consecutive blood donors' records covering the period between January 2003 and December 2007 was conducted. Logistic regression analysis was used to determine risk factors associated with HIV, HBV, HCV and syphilis infections.ResultsFrom the total of 6361 consecutive blood donors, 607 (9.5%) had serological evidence of infection with at least one pathogen and 50 (0.8%) had multiple infections. The overall seroprevalence of HIV, HBV, HCV and syphilis was 3.8%, 4.7%, 0.7%, and 1.3% respectively. Among those with multiple infections, the most common combinations were HIV - syphilis 19 (38%) and HIV - HBV 17 (34%). The seropositivity of HIV was significantly increased among female blood donors, first time donors, housewives, merchants, soldiers, drivers and construction workers. Significantly increased HBV seropositivity was observed among farmers, first time donors and age groups of 26 - 35 and 36 - 45 years. Similarly, the seroprevalence of syphilis was significantly increased among daily labourers and construction workers. Statistically significant association was observed between syphilis and HIV infections, and HCV and HIV infections. Moreover, significantly declining trends of HIV, HCV and syphilis seropositivity were observed over the study period.ConclusionsA substantial percentage of the blood donors harbour HIV, HBV, HCV and syphilis infections. Strict selection of blood donors and comprehensive screening of donors' blood using standard methods are highly recommended to ensure the safety of blood for recipient.

Bartonellaspp. Infections, Thailand

<i>Bartonella</i>spp. Infections, Thailand

Serological evidence of infection with &lt;i&gt;Rickettsia typhi&lt;/i&gt; among inmates in Jos Prison, Nigeria.

Background: Rickettsia typhi a gram negative obligate intracellular bacterium has been described as the etiological agent of murine typhus an infectious disease associated with febrile illnesses and wide range of non-specific clinical signs. It can be transmitted by the rat flea, Xenopsylla cheopsis. Aim: The aim of the study is to determine the prevalence of R. typhi among inmates in Jos prison. Methodology: Sera from 93 prison inmates were examined for R. typhi IgM antibodies using enzyme immunoassay. Age, residence area prior to incarceration, sanitary conditions/ personal hygiene, history of fleabite/contact with animals and numbers in cell were surveyed. Results: Overall Rickettsia typhi seroprevalence was 71.1%. Rickettsia typhi was present in 77.6% and 60.0% from subjects resident in urban and rural areas prior to incarceration. The age group of 42-60 years had the highest prevalence of 87.5%. 59/78 (75.6%) reported very poor sanitary conditions. All the inmates were exposed to fleabite and had contact with animals. Poor sanitary conditions/personal hygiene, history of fleabite/contact with animals and overcrowding in the prison were found to be significantly associated with the infection in this population (p< 0.05). Our data seem to reveal the presence of Rickettsia typhi among prison inmates in Jos. Conclusion: Rodent and flea control programmes need be intensified as well as improvement of sanitary conditions in our prisons is necessary to reduce the incidence of the disease. We urge that serologic testing be also considered for R. typhi in cases of febrile illnesses of unknown origin in our environment.Keywords: Rickettsia typhi , Prison inmates, Jos-Nigeria

Serologic Evidence of Infection with H5 Subtype Influenza Virus in Apparently Healthy Local Chickens in Kaduna State, Nigeria

A serologic survey for antibodies against H5 subtype influenza virus in 605 apparently healthy local chickens using a hemagglutination inhibition test was carried out in 12 local government areas of Kaduna state, Nigeria. An overall prevalence of 18.1% was recorded, with a higher prevalence of 27.3% in six local government areas that have not reported outbreaks of highly pathogenic avian influenza (HPAI) H5N1 virus and a lower prevalence of 7.5% in six local government areas that had reported and confirmed outbreaks of HPAI H5N1 virus between 2006 and 2007. There was association between the presence of ducks and detection of H5 antibodies (P = 0.000, odds ratio = 0.22). The implication of this finding is discussed, although a virologic investigation to verify the findings of this study is highly recommended.

Serologic Evidence of Infection with H5 Subtype Influenza Virus in Apparently Healthy Local Chickens in Kaduna State, Nigeria

Serologic Evidence of Infection with H5 Subtype Influenza Virus in Apparently Healthy Local Chickens in Kaduna State, Nigeria

A Multiplex Real-Time Reverse Transcription Polymerase Chain Reaction Assay for Detection and Differentiation ofBluetongue VirusandEpizootic Hemorrhagic Disease VirusSerogroups

Bluetongue virus (BTV) causes disease in domestic and wild ruminants and results in significant economic loss. The closely related Epizootic hemorrhagic disease virus (EHDV) has been associated with bluetongue-like disease in cattle. Although U.S. EHDV strains have not been experimentally proven to cause disease in cattle, there is serologic evidence of infection in cattle. Therefore, rapid diagnosis and differentiation of BTV and EHDV is required. The genetic sequence information and bioinformatic analysis necessary to design a real-time reverse transcription polymerase chain reaction (RT-PCR) assay for the early detection of indigenous and exotic BTV and EHDV is described. This sequence data foundation focused on 2 conserved target genes: one that is highly expressed in infected mammalian cells, and the other is highly expressed in infected insect cells. The analysis of all BTV and EHDV prototype strains indicated that a complex primer design was necessary for both a virus group-comprehensive and virus group-specific gene amplification diagnostic test. This information has been used as the basis for the development of a rapid multiplex BTV-EHDV real-time RT-PCR that detects all known serotypes of both viruses and distinguishes between BTV and EHDV serogroups. The sensitivity of this rapid, single-tube, real-time RT-PCR assay is sufficient for diagnostic application, without the contamination problems associated with standard gel-based RT-PCR, especially nested RT-PCR tests.