How to determine rabies in dogs? - briefly
To determine rabies in dogs, veterinarians primarily rely on clinical observation of symptoms and laboratory testing of brain tissue or saliva. Symptoms include aggressive behavior, paralysis, and excessive drooling, while lab tests confirm the presence of the virus.
How to determine rabies in dogs? - in detail
Rabies is a fatal viral disease that affects the nervous system of mammals, including dogs. Determining whether a dog has rabies involves several steps and considerations due to the complex nature of the virus. Here's a detailed approach:
-
Clinical Observation: The first step in determining rabies is observing the dog's behavior for any signs of illness. Rabies typically progresses through three stages—prodromal, furious, and paralytic. In the prodromal stage, dogs may exhibit subtle changes such as lethargy or loss of appetite. The furious stage is characterized by increased aggression, restlessness, and irritability. During the paralytic stage, dogs show signs of muscle weakness and paralysis.
-
Laboratory Diagnosis: Due to the high mortality rate associated with rabies, clinical diagnosis alone is not sufficient. Laboratory testing is crucial for a definitive diagnosis. The most common method is the direct fluorescent antibody test (dFA), which detects viral antigens in brain tissue samples. This test is highly sensitive and specific but requires specialized equipment and trained personnel.
-
Specimen Collection: To perform the dFA test, a sample of brain tissue from the suspected dog must be collected. In deceased animals, this involves extracting the brain stem. For live animals, collection of cerebrospinal fluid or saliva can sometimes be used, although these methods are less reliable than brain tissue analysis.
-
Histopathological Examination: While dFA is the gold standard for rabies diagnosis, histopathological examination of brain tissue can also be informative. This involves examining brain sections under a microscope to look for characteristic Negri bodies—eosinophilic inclusions found in infected neurons. However, this method requires expertise and may not detect low levels of infection.
-
Other Diagnostic Methods: In addition to dFA and histopathology, other diagnostic methods include reverse transcription-polymerase chain reaction (RT-PCR) for viral RNA detection and the rapid immunodiagnostic test (RIDT), which can be used in field settings but requires confirmation with a more specific test.
-
Public Health Considerations: If rabies is suspected, immediate action is essential to prevent further transmission. This includes isolating the dog, notifying public health authorities, and ensuring that anyone who may have been exposed receives prompt post-exposure prophylaxis (PEP).
In conclusion, determining rabies in dogs involves a combination of clinical observation, laboratory testing, and public health measures. Due to the severe consequences of rabies, any suspected case should be handled with caution and reported to appropriate authorities for further investigation and management.