Serological evidence of SARS-CoV-2 infection among white-tailed deer has been reported from Illinois, Michigan, Pennsylvania, and New York. This study was conducted to determine whether deer in Texas also had evidence of SARS-CoV-2 infection. Archived sera samples collected from deer in Travis County, Texas, during 2018, before and during the pandemic in 2021 were tested for neutralizing antibody to this virus by a standard plaque reduction neutralization assay. SARS-CoV-2 antibody was not detected in 40 deer sera samples collected during 2018, but 37% (20/54) samples collected in 2021 were positive for antibody. The seroprevalence rate between males and females differed significantly (p < 0.05) and the highest rate (82%) was detected in the 1.5-year-old animals. These findings extended the geographical range of prior SARS-CoV-2 infection among white-tailed deer in the United States and further confirm that infection was common among this species.
26 September 2022 in The American Journal of Tropical Medicine and Hygiene
: The objective of this study was to determine the etiology of febrile illnesses among patients from October 1, 1993 through September 30, 1999, in the urban community of Iquitos in the Amazon River Basin of Peru. Epidemiological and clinical data as well as blood samples were obtained from consenting patients at hospitals, health clinics and private residences. Samples were tested for arboviruses in cell cultures and for IgM and IgG antibodies by ELISA. Blood smears were examined for malaria, and sera were tested for antibodies to Leptospira spp. by ELISA and microscopic agglutination. Among 6,607 febrile patients studied, dengue viruses caused 14.6% of the cases, and Venezuelan equine encephalitis virus caused 2.5%, Oropouche virus 1.0%, Mayaro virus 0.4%, and other arboviruses caused 0.2% of the cases. Also, 22.9% of 4,844 patients tested were positive for malaria, and of 400 samples tested, 9% had evidence of acute leptospirosis. Although the study was not designed to assess the importance of these pathogens as a cause of human morbidity in the total population, these results indicate that arboviruses, leptospirosis, and malaria were the cause of approximately 50% of the febrile cases. Although the arboviruses that were diagnosed can produce asymptomatic infections, our findings increased the overall understanding of the relative health burden of these infections, as well as baseline knowledge needed for designing and implementing further studies to better assess the health impact and threat of these pathogens in the Amazon Basin of Peru.
: The Rift Valley fever virus (RVFV) MP-12 vaccine is a promising human and veterinary vaccine. Although the vaccine elicited neutralizing antibody (nAb) in human volunteers, the minimal antibody titer that is needed to afford protection is unknown. Therefore, this study was conducted to determine the minimal nAb titer elicited by the RVFV MP-12 vaccine in human volunteers that protected mice against lethal RVFV challenge as a surrogate assessment of the protective efficacy of the vaccine. Among volunteers who were vaccinated with the MP-12 vaccine during a phase II trial, sera with antibody titers of 1:20 collected 5 years post-vaccination (PV), 1:40 titer collected 2 years PV, and 1:80 titer collected 1 year PV was passively transferred to groups of BALB/c mice. Blood samples were obtained 1 day after passive transfer to determine the RVFV neutralizing nAb titer before challenge with pathogenic RVFV (strain ZH501). Our results indicated that 1 day after passive transfer of the immune sera, an approximate 4-fold reduction in circulating nAb titers was detected in the mice. The presence of RVFV nAb titers in the range of 1:5 to 1:20 were generally protective (75–100% survival). These results suggested that circulating titers of 1:5 or higher offer a high degree of protection by MP-12-elicited antibody in human volunteers. Also, the findings highlighted the value of using the BALB/c mouse RVFV challenge model as a surrogate for evaluating the protective nAb responses elicited by MP-12 and possible use for evaluating the efficacy of other RVFV vaccine candidates.
31 January 2019 in Onderstepoort Journal of Veterinary Research
The Onderstepoort Journal of Veterinary Research (OJVR), is the official publication of the Onderstepoort Veterinary Institute. It publishes scientific papers reporting original research on diseases and disease vectors of livestock and wildlife with a focus on Africa, but with results of more than local interest.
1 February 2019 in Vector-Borne and Zoonotic Diseases
Arboviruses are significant causes of human and animal diseases, globally. In the Rio Grande Valley of the United States-Mexico border region, endemic transmission of Dengue (DENV), Zika (ZIKV), and West Nile (WNV) viruses have been documented as a cause of human disease. Otherwise, very little is known about the distribution of arboviruses and their possible cause of human disease in other areas of the United States-Mexico border region. Therefore, a pilot serosurvey was conducted to determine if there was evidence of DENV and WNV infection among a human cohort in Anapra, Ciudad Juarez, Mexico. Baseline blood samples were obtained from 78 participants during May-June, 2015 and from 60 of the same participants again during November-December, 2015, and all the samples were tested for DENV and WNV indirect immunoglobulin G antibodies by an enzyme-linked immunosorbent assay and plaque reduction neutralization test (PRNT). The results showed that 14.1% (n = 11) of the 78 participants had neutralizing antibody to DENV and 5.13% (n = 4) had WNV-neutralizing antibody. Among 48 of 60 participants who were negative for DENV and WNV antibody during the baseline survey, 10.4% (n = 5) had acquired antibody to DENV (n = 4) and WNV (n = 1) by the second survey during November-December, 2015. These data support the local transmission of DENV and WNV in the Anapra, Ciudad Juarez community and therefore warrant further epidemiological studies to better understand the dynamics of transmission of these viruses in this United States-Mexico border city.