scholarly journals Experimental Challenge of Sheep and Cattle with Dugbe Orthonairovirus, a Neglected African Arbovirus Distantly Related to CCHFV

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 372
Author(s):  
Julia Hartlaub ◽  
Felicitas von Arnim ◽  
Christine Fast ◽  
Ali Mirazimi ◽  
Markus Keller ◽  
...  
Keyword(s):  
Neutralization Test ◽  
Clinical Signs ◽  
Febrile Illness ◽  
Hemorrhagic Fever ◽  
African Countries ◽  
Transmission Cycle ◽  
N Protein ◽  
Diagnostic Assays ◽  
Subcutaneous Inoculation ◽  
Experimental Challenge

Dugbe orthonairovirus (DUGV) is a tick-borne arbovirus within the order Bunyavirales. DUGV was first isolated in Nigeria, but virus isolations in ten further African countries indicate that DUGV is widespread throughout Africa. Humans can suffer from a mild febrile illness, hence, DUGV is classified as a biosafety level (BSL) 3 agent. In contrast, no disease has been described in animals, albeit serological evidence exists that ruminants are common hosts and may play an important role in the transmission cycle of this neglected arbovirus. In this study, young sheep and calves were experimentally inoculated with DUGV in order to determine their susceptibility and to study the course of infection. Moreover, potential antibody cross-reactivities in currently available diagnostic assays for Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) were assessed as DUGV is distantly related to CCHFV. Following subcutaneous inoculation, none of the animals developed clinical signs or viremia. However, all ruminants seroconverted, as demonstrated by two DUGV neutralization test formats (micro-virus neutralization test (mVNT), plaque reduction (PRNT)), by indirect immunofluorescence assays and in bovines by a newly developed DUGV recombinant N protein ELISA. Sera did not react in commercial CCHFV ELISAs, whereas cross-reactivities were observed by immunofluorescence and immunoblot assays.

scholarly journals Cross-Reaction or Co-Infection? Serological Discrimination of Antibodies Directed against Dugbe and Crimean-Congo Hemorrhagic Fever Orthonairovirus in Nigerian Cattle

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1398
Author(s):  
Julia Hartlaub ◽  
Oluwafemi B. Daodu ◽  
Balal Sadeghi ◽  
Markus Keller ◽  
James Olopade ◽  
...  
Keyword(s):  
Indirect Immunofluorescence ◽  
Hemorrhagic Fever ◽  
Immunofluorescence Assay ◽  
Cross Reaction ◽  
African Countries ◽  
Crimean Congo Hemorrhagic Fever ◽  
Transmission Cycle ◽  
N Protein ◽  
Seroprevalence Data ◽  
Human Infections

Dugbe orthonairovirus (DUGV) and Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV) are tick-borne arboviruses within the order Bunyavirales. Both viruses are endemic in several African countries and can induce mild (DUGV, BSL 3) or fatal (CCHFV, BSL 4) disease in humans. Ruminants play a major role in their natural transmission cycle. Therefore, they are considered as suitable indicator animals for serological monitoring studies to assess the risk for human infections. Although both viruses do not actually belong to the same serogroup, cross-reactivities have already been reported earlier—hence, the correct serological discrimination of DUGV and CCHFV antibodies is crucial. In this study, 300 Nigerian cattle sera (150 CCHFV seropositive and seronegative samples, respectively) were screened for DUGV antibodies via N protein-based ELISA, indirect immunofluorescence (iIFA) and neutralization assays. Whereas no correlation between the CCHFV antibody status and DUGV seroprevalence data could be demonstrated with a newly established DUGV ELISA, significant cross-reactivities were observed in an immunofluorescence assay. Moreover, DUGV seropositive samples did also cross-react in a species-adapted commercial CCHFV iIFA. Therefore, ELISAs seem to be able to reliably differentiate between DUGV and CCHFV antibodies and should preferentially be used for monitoring studies. Positive iIFA results should always be confirmed by ELISAs.

scholarly journals New Zealand sheep with scrapie-susceptible PrP genotypes succumb to experimental challenge with a sheep-passaged scrapie isolate (SSBP/1)

2002 ◽  
Vol 83 (5) ◽  
pp. 1247-1250 ◽  
Author(s):  
E. F. Houston ◽  
S. I. Halliday ◽  
M. Jeffrey ◽  
W. Goldmann ◽  
N. Hunter
Keyword(s):  
New Zealand ◽  
Histopathological Examination ◽  
Clinical Signs ◽  
Lymphoid Tissues ◽  
High Frequencies ◽  
Incubation Periods ◽  
Scrapie Infection ◽  
Prp Gene ◽  
Subcutaneous Inoculation ◽  
Experimental Challenge

Scrapie does not occur in New Zealand (NZ), although PrP gene alleles associated with susceptibility to the disease are found at relatively high frequencies in NZ sheep. The hypothesis that scrapie is a genetic disease of sheep is thus unlikely to be true. To confirm that NZ sheep are actually susceptible to scrapie infection, NZ sheep of various PrP genotypes were challenged by subcutaneous inoculation with a sheep-passaged scrapie isolate (SSBP/1). Showing similar PrP genetics to that seen in UK sheep, all NZ sheep carrying the VRQ PrP allele developed clinical signs typical of scrapie, with characteristic neurodegenerative changes and PrPSc evident on histopathological examination of their brains and lymphoid tissues. The incubation periods recorded in NZ sheep were generally shorter than those found in UK sheep. The results confirm that New Zealand sheep are as susceptible as their UK counterparts to experimental scrapie infection by subcutaneous inoculation.

scholarly journals Deciphering Antibody Responses to Orthonairoviruses in Ruminants

2021 ◽  
Vol 9 (7) ◽  
pp. 1493
Author(s):  
Julia Hartlaub ◽  
Markus Keller ◽  
Martin H. Groschup
Keyword(s):  
Indirect Immunofluorescence ◽  
Neutralization Test ◽  
Hemorrhagic Fever ◽  
Antibody Responses ◽  
Virus Neutralization Test ◽  
Human Pathogen ◽  
N Protein ◽  
Cross Reactions ◽  
Test Formats ◽  
Heterologous Virus

Antibody cross-reactivities between related viruses are common diagnostic challenges, resulting in reduced diagnostic specificities and sensitivities. In this study, antibody cross-reactions between neglected members of the genus Orthonairovirus—Hazara (HAZV), Dugbe (DUGV), and Nairobi sheep disease orthonairovirus (NSDV)—were investigated. Mono-specific ovine and bovine sera following experimental infections as well immunization trials with HAZV, DUGV, and NSDV were tested in homologous and heterologous virus-specific assays, namely indirect ELISAs based on recombinant N protein, indirect immunofluorescence assays (iIFA), and two neutralization test formats (plaque reduction neutralization test (PRNT) and micro-virus neutralization test (mVNT)). The highest specificities were achieved with the ELISAs, followed by the mVNT, iIFA, and PRNT. Cross-reactivities were mainly observed within the Nairobi sheep disease serogroup–but surprisingly, HAZV antibodies in PRNT did also neutralize NSDV and DUGV. In conclusion, we recommend ELISAs and mVNTs for a discriminative diagnostic approach to differentiate between these antibodies. NSDV antisera were also used in serological assays for the detection of antibodies against the human pathogen Crimean-Congo hemorrhagic fever orthonairovirus (CCHFV). Interestingly, all CCHFV ELISAs (In-house and commercial) achieved high diagnostic specificities, whereas significant cross-reactivities were observed in a CCHFV iIFA. Previously, similar results were obtained when analyzing the HAZV and DUGV antisera.

scholarly journals Diagnostic Value of Clinical Features to Distinguish Enteric Fever From Other Febrile Illnesses in Bangladesh, Nepal, and Pakistan

2020 ◽  
Vol 71 (Supplement_3) ◽  
pp. S257-S265 ◽  
Author(s):  
Kristen Aiemjoy ◽  
Dipesh Tamrakar ◽  
Shampa Saha ◽  
Shiva R Naga ◽  
Alexander T Yu ◽  
...  
Keyword(s):  
Blood Culture ◽  
Clinical Features ◽  
Diagnostic Performance ◽  
Enteric Fever ◽  
Random Effect ◽  
Clinical Signs ◽  
Febrile Illness ◽  
Diagnostic Value ◽  
Case Definition ◽  
Mixed Effect

Abstract Background Enteric fever, a bacterial infection caused by Salmonella enterica serotypes Typhi and Paratyphi A, frequently presents as a nonlocalizing febrile illness that is difficult to distinguish from other infectious causes of fever. Blood culture is not widely available in endemic settings and, even when available, results can take up to 5 days. We evaluated the diagnostic performance of clinical features, including both reported symptoms and clinical signs, of enteric fever among patients participating in the Surveillance for Enteric Fever in Asia Project (SEAP), a 3-year surveillance study in Bangladesh, Nepal, and Pakistan. Methods Outpatients presenting with ≥3 consecutive days of reported fever and inpatients with clinically suspected enteric fever from all 6 SEAP study hospitals were eligible to participate. We evaluated the diagnostic performance of select clinical features against blood culture results among outpatients using mixed-effect regression models with a random effect for study site hospital. We also compared the clinical features of S. Typhi to S. Paratyphi A among both outpatients and inpatients. Results We enrolled 20 899 outpatients, of whom 2116 (10.1%) had positive blood cultures for S. Typhi and 297 (1.4%) had positive cultures for S. Paratyphi A. The sensitivity of absence of cough was the highest among all evaluated features, at 65.5% (95% confidence interval [CI], 55.0–74.7), followed by measured fever at presentation at 59.0% (95% CI, 51.6–65.9) and being unable to complete normal activities for 3 or more days at 51.0% (95% CI, 23.8–77.6). A combined case definition of 3 or more consecutive days of reported fever and 1 or more of the following (a) either the absence of cough, (b) fever at presentation, or (c) 3 or more consecutive days of being unable to conduct usual activity--yielded a sensitivity of 94.6% (95% CI, 93.4–95.5) and specificity of 13.6% (95% CI, 9.8–17.5). Conclusions Clinical features do not accurately distinguish blood culture–confirmed enteric fever from other febrile syndromes. Rapid, affordable, and accurate diagnostics are urgently needed, particularly in settings with limited or no blood culture capacity.

Neospora caninum (Protozoa: Apicomplexa) infections in rats

1990 ◽  
Vol 68 (7) ◽  
pp. 1595-1599 ◽  
Author(s):  
David S. Lindsay ◽  
J. P. Dubey
Keyword(s):  
Rattus Norvegicus ◽  
Neospora Caninum ◽  
Clinical Signs ◽  
Hepatic Necrosis ◽  
Female Rats ◽  
Methylprednisolone Acetate ◽  
Laboratory Rats ◽  
Experimental Inoculation ◽  
Caninum Tachyzoites ◽  
Subcutaneous Inoculation

The susceptibility of laboratory rats (Rattus norvegicus) to experimental inoculation with tachyzoites of Neospora caninum was examined. Groups of female rats were intramuscularly injected with 0, 2, or 4 mg of methylprednisolone acetate (MPA) 7 days prior to, and on the day of, subcutaneous inoculation with 0 or 1.5 × 105 tachyzoites. Clinical signs of disease or deaths did not occur in rats given nothing or only N. caninum tachyzoites. Rats given only 4 mg MPA failed to grow as well as rats given nothing or only N. caninum tachyzoites but were otherwise healthy. All of 20 rats given 4 mg MPA and tachyzoites died of hepatitis and pneumonia within 12 days postinoculation. Hepatic necrosis was the most striking lesion seen in these rats, and other milder lesions consisted of pneumonia, encephalitis, and myositis. The response of rats given 2 mg MPA and tachyzoites was less severe. Three of 20 rats died with encephalitis, myositis, hepatitis, and pancreatitis. Mild lesions, but no N. caninum tachyzoites, were seen in 3 of 14 rats inoculated only with tachyzoites. Rats given the 4 mg MPA treatment and inoculated with N. caninum tachyzoites appear to be suitable subjects for examining acute neosporosis and could be used in studies designed to examine treatment of acute disease.

scholarly journals Active Circulation of Madariaga Virus, a Member of the Eastern Equine Encephalitis Virus Complex, in Northeast Brazil

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 983
Author(s):  
Laura H. V. G. Gil ◽  
Tereza Magalhaes ◽  
Beatriz S. A. S. Santos ◽  
Livia V. Oliveira ◽  
Edmilson F. Oliveira-Filho ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Case Fatality ◽  
Febrile Illness ◽  
Encephalitis Virus ◽  
Northeast Brazil ◽  
Eastern Equine Encephalitis Virus ◽  
Eastern Equine Encephalitis ◽  
Vaccination Programs ◽  
Transmission Cycle ◽  
Equine Encephalitis Virus

Madariaga virus (MADV) is a member of the eastern equine encephalitis virus (EEEV) complex that circulates in Central and South America. It is a zoonotic, mosquito-borne pathogen, belonging to the family Togaviridae. Disturbances in the natural transmission cycle of this virus result in outbreaks in equines and humans, leading to high case fatality in the former and acute febrile illness or neurological disease in the latter. Although a considerable amount of knowledge exists on the eco-epidemiology of North American EEEV strains, little is known about MADV. In Brazil, the most recent isolations of MADV occurred in 2009 in the States of Paraíba and Ceará, northeast Brazil. Because of that, health authorities have recommended vaccination of animals in these regions. However, in 2019 an equine encephalitis outbreak was reported in a municipality in Ceará. Here, we present the isolation of MADV from two horses that died in this outbreak. The full-length genome of these viruses was sequenced, and phylogenetic analyses performed. Pathological findings from postmortem examination are also discussed. We conclude that MADV is actively circulating in northeast Brazil despite vaccination programs, and call attention to this arbovirus that likely represents an emerging pathogen in Latin America.

A new multivalent (DHPPi/L4R) canine combination vaccine prevents infection, shedding and clinical signs following experimental challenge with four Leptospira serovars

Vaccine ◽  
2013 ◽  
Vol 31 (31) ◽  
pp. 3131-3134 ◽  
Author(s):  
Stephen Wilson ◽  
Catrina Stirling ◽  
Anne Thomas ◽  
Vickie King ◽  
Edita Plevová ◽  
...  
Keyword(s):  
Clinical Signs ◽  
Combination Vaccine ◽  
Leptospira Serovars ◽  
Experimental Challenge

scholarly journals Monoclonal Antibody-Based Antigen Capture Enzyme-Linked Immunosorbent Assay Reveals High Sensitivity of the Nucleocapsid Protein in Acute-Phase Sera of Severe Acute Respiratory Syndrome Patients

2005 ◽  
Vol 12 (1) ◽  
pp. 135-140 ◽  
Author(s):  
Biao Di ◽  
Wei Hao ◽  
Yang Gao ◽  
Ming Wang ◽  
Ya-di Wang ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Acute Phase ◽  
Detection Rate ◽  
Neutralization Test ◽  
Protein Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
N Protein ◽  
Antigen Capture ◽  
Healthy Donors

ABSTRACT Accurate and timely diagnosis of severe acute respiratory syndrome coronavirus (SARS-CoV) infection is a critical step in preventing another global outbreak. In this study, 829 serum specimens were collected from 643 patients initially reported to be infected with SARS-CoV. The sera were tested for the N protein of SARS-CoV by using an antigen capture enzyme-linked immunosorbent assay (ELISA) based on monoclonal antibodies against the N protein of SARS-CoV and compared to 197 control serum samples from healthy donors and non-SARS febrile patients. The results of the N protein detection analysis were directly related to the serological analysis data. From 27 SARS patients who tested positive with the neutralization test, 100% of the 24 sera collected from 1 to 10 days after the onset of symptoms were positive for the N protein. N protein was not detected beyond day 11 in this group. The positive rates of N protein for sera collected at 1 to 5, 6 to 10, 11 to 15, and 16 to 20 days after the onset of symptoms for 414 samples from 298 serologically confirmed patients were 92.9, 69.8, 36.4, and 21.1%, respectively. For 294 sera from 248 serological test-negative patients, the rates were 25.6, 16.7, 9.3, and 0%, respectively. The N protein was not detected in 66 patients with cases of what was initially suspected to be SARS but serologically proven to be negative for SARS and in 197 serum samples from healthy donors and non-SARS febrile patients. The specificity of the assay was 100%. Furthermore, of 16 sera collected from four patients during the SARS recurrence in Guangzhou, 5 sera collected from 7 to 9 days after the onset of symptoms were positive for the N protein. N protein detection exhibited a high positive rate, 96 to 100%, between day 3 and day 5 after the onset of symptoms for 27 neutralization test-positive SARS patients and 298 serologically confirmed patients. The N protein detection rate continually decreased beginning with day 10, and N protein was not detected beyond day 19 after the onset of symptoms. In conclusion, an antigen capture ELISA reveals a high N protein detection rate in acute-phase sera of patients with SARS, which makes it useful for early diagnosis of SARS.

Serological evidence of Mayaro virus infection in blood donors from São Carlos, São Paulo, Brazil

2020 ◽  
Vol 114 (9) ◽  
pp. 693-696 ◽  
Author(s):  
Marilia Farignoli Romeiro ◽  
Marcílio Jorge Fumagalli ◽  
Ana Beatriz dos Anjos ◽  
Luiz Tadeu Moraes Figueiredo
Keyword(s):  
Clinical Signs ◽  
Southeastern Brazil ◽  
Igg Antibodies ◽  
Neutralization Activity ◽  
Diagnostic Assays ◽  
Diagnostic Confusion ◽  
Arboviral Diseases ◽  
Mayaro Virus ◽  
Insect Bites ◽  
Human Infections

Abstract Background Human infections by Mayaro virus (MAYV) occur by insect bites upon exposure to rural or sylvatic areas. Information regarding MAYV transmission is limited due to a lack of commercial diagnostic assays and diagnostic confusion on account of similarities of clinical signs with other co-circulating arboviral diseases. Methods A serological survey of MAYV and Chikunguya virus (CHIKV) antibodies was performed by ELISA. Between 2017 and 2018, 5608 blood donor samples were tested. Results Specific IgM and IgG antibodies to MAYV were detected respectively in 36 and 11 samples, indicating a total seroprevalence of approximately 0.83%. Neutralization activity was observed in two IgG positive sera. Additionally, eight distinct samples had IgM antibodies to CHIKV alone. Conclusions Our data suggest previously unreported circulation of MAYV in São Carlos city, from southeastern Brazil.

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