Final answer:
It is true that poliovirus can be found in the stool or throat before the onset of clinical illness. This asymptomatic shedding contributes to its spread, emphasizing the need for vaccination.
Step-by-step explanation:
True, poliovirus can be recovered from the stool or throat even before the onset of illness. After the virus enters through the mouth, it initially replicates in the pharynx and gastrointestinal tract. Before the appearance of any symptoms, poliovirus is typically present in the throat and in the stool.
This initial phase of asymptomatic shedding is crucial as it contributes to the spread of the virus, especially in environments with close contact or inadequate sanitation. Tests like reverse transcriptase PCR (RT-PCR) are used for the direct detection of poliovirus from these samples. Moreover, understanding that the virus can be excreted before symptom onset highlights the importance of polio vaccination as a preventative measure. Jonas Salk's development of the first polio vaccine dramatically reduced the global burden of the disease.