Comparative evaluation of some techniques used for the detection of rabies virus.

Background: Neurotropic viruses in the family Rhabdoviridae, genus Lyssavirus, are what cause rabies, an acute, progressive, and highly lethal encephalomyelitis. Aim: Evaluation of the used diagnostic techniques to determine the most simple; rapid and accurate test for rabies virus (RABV) recognition in different specimens aiming to reach a rapid diagnosis as a step aid in the disease control and to prevent or even minimize the suspected hazard. Method: The used techniques included an infection trial of Swiss mice with the mice-adapted challenge rabies virus followed by the detection of the virus in the infected mices' brains. Virus detection was carried out through the application BHK21 cell line infection; fluorescent antibody technique; latex agglutination test (LAT); direct enzyme-linked immunosorbent assay (ELISA); rabies antigen detection kit ELISA; conventional polymerase chain reaction (PCR). Results: It was found that virus inoculation in mice and BHK21 cell lines needs 5-7 days with positivity of 90% and 100%, respectively. Rapid antigen kit was able to detect rabies antigen in mice brains suspension and BHK21 infected fluid within 3-5 minutes with percentages of 60% and 55.5%, respectively. In 1-1.5 hours, the direct fluorescent antibody method (DFAT) detected 90% and 100% of the rabies antigen in BHK21 cell line infection and brain impressions, respectively. Latex agglutination showed clear results with 88.8% with BHK21 infected fluid within 3-5 minutes while it did not carry out on brain emulsions to prevent falsely positive results brought on by the presence of tissue fragments. Conventional one-step PCR revealed 100% positivity with either brain or cell culture preparations within 2 days. Direct ELISA showed 88.8% positivity with BHK21 infected fluid with 1 day of work. Conclusion: Mice inoculation test, cell culture infection; DFAT and PCR are the most accurate techniques for the detection of RABV with a positivity of 90%-100% followed by LAT and ELISA with a positivity of 88.8%, and lastly, rabies antigen ELISA kit (RAK) with a positivity of 55.5%-60% taking in consideration the required time for each. In addition, the positivity % of the applied tests revealed their sensitivity and specificity.

Investigation of the effect of mutual vaccination with pest des petits ruminants and polyvalent foot and mouth disease vaccines on the immune response of sheep.

Background: Pest des petits ruminants (PPRs) and foot and mouth disease (FMD) are two viral infectious diseases affecting sheep dramatically causing great economic losses. Therefore, attention should be directed toward their control, especially through the application of well-designed vaccination schedules with specific potent vaccines. Aim: Determination of the possibility of sheep vaccination with PPR and FMD vaccines in a mutual schedule. Methods: Different groups of sheep have vaccinated with live attenuated PPR vaccine and inactivated polyvalent FMD vaccine in a mutual manner (one before the other at weekly intervals or simultaneously) followed by monitoring of the induced immunity to both vaccines using serum neutralization test (SNT) and enzyme linked immune sorbent assay (ELISA). Results: SNT and ELISA revealed that there was no antagonizing effect of any vaccine on the immune response to the mutual vaccination of sheep to the other where the obtained antibody titers in single vaccinated sheep groups were similar to those in the simultaneous vaccinated group. Conclusion: Simultaneous vaccination of sheep with PPR and polyvalent FMD vaccine is of applicable benefit saving time, effort, and stress factors on the animals.

Preparation and the assessed efficacy of oral baits for the vaccination of free-roaming dogs against rabies.

Background and Aim: Rabies is considered a highly fatal zoonotic disease and many deaths in humans have been associated with dog bites. This study was designed to prepare an oral anti-rabies vaccine in the form of baits to eliminate the disease in free-roaming dogs and subsequently protect humans from dog bites. Materials and Methods: The Evelyn Rokintniki Abelseth (ERA) rabies virus strain was propagated in baby hamster kidney cell cultures and adjusted to the recommended dose for application. Four forms of oral baits were employed with the rabies vaccine, which was evaluated for safety, acceptability, and potency in different dog groups. Enzyme-Linked Immunosorbent Assay (ELISA) and the serum neutralization test (SNT) were used to determine the protective rabies antibody titer in the sera of vaccinated dogs. Results: According to the results, a dose of 3 mL of the ERA strain, containing a viral titer of 107.6 TCID50/mL, induced a mean antibody titer of 25.6 by SNT, and the PI% was 75.7 by Block ELISA, providing a protective level of the rabies antibody in 100% of vaccinated dogs. All used baits were found to be safe, inducing no abnormal general post-vaccination signs (the signs are limited to mild fever, mild loss of appetite, and mild-to-moderate loss of energy for 24-36 h after vaccination). Conclusion: It was found that most of the accepted and highly potent bait types consisted of a mixture of wheat flour, vegetable oil, sodium alginate, corn starch, meat meal, cellulose gum, and water. This dog meal was covered with bran and edible wax to seal the bait cavity after inserting the vaccine sachet. This bait was able to induce a protective level of rabies antibodies in 100% of vaccinated dogs after receiving one bait/dog. Hence, such a bait could be recommended for use in the protection of free-roaming dogs and the elimination of the disease.

COVID-19: Post-recovery long-term symptoms among patients in Saudi Arabia.

BACKGROUND: After recovery from acute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many patients experience long-term symptoms in different body systems. The aim of the present study was to identify these symptoms, their severity, and their duration as a first step in building a system to classify post-recovery long-term symptoms of coronavirus disease 2019 (COVID-19). METHODS: An online-based cross-sectional survey was administered between September and October 2020. Data regarding the severity of post-recovery symptoms and their duration were collected using an Arabic questionnaire divided into six categories encompassing the 20 most prevalent symptoms. RESULTS: A total of 979 patients recovered from COVID-19 in Saudi Arabia in the study period, of whom 53% were male and 47% were female. The most common symptoms included general fatigue and weakness (73% each), with moderate severity of neurological symptoms including mood changes (41%) and insomnia (39%). Among the special senses, loss of smell and taste of marked severity were reported by 64% and 55% among respiratory symptoms, cough of mild severity (47%), and dyspnea of moderate severity (43%). Loss of appetite of moderate severity was reported in 42%, and diarrhea, abdominal pain, and nausea of mild severity were reported by 53%, 50%, and 44% of respondents, respectively. CONCLUSIONS: Long-term symptoms after recovery from COVID-19 warrant patient follow-up. The authors propose a classification system as a starting point to guide the identification and follow-up of long-term symptoms post-recovery, and recommend larger-scale studies to broaden the definition of recovery from COVID-19, which appears to have two phases, acute and chronic.