Final answer:
Long intervals between infectiousness onset and disease symptoms do increase transmission chances because individuals can unknowingly spread the infection during the incubation period.
Step-by-step explanation:
True, long intervals between the onset of infectiousness and disease can increase the chances of transmission. This is because during the incubation period, which is the time between infection and the first appearance of symptoms, an individual may be infectious without being aware of it. This can lead to a greater number of contacts and therefore a higher risk of spread before measures to contain the infection are implemented. Infectious diseases can have varying periods of communicability, and factors such as the strength of the pathogen, the strength of the host's immune response, and the type of infection can affect the length of the incubation period, potentially leading to asymptomatic transmission.