Which of the following are signs of severe or acute pesticide poisoning?

Severe or acute pesticide poisoning can manifest through a variety of symptoms that indicate a significant response to toxic exposure. Intense thirst, fever, and vomiting are indicative of systemic reactions that occur when the body is dealing with high levels of toxic substances. These symptoms suggest not only an acute reaction but also the body's efforts to expel the toxins it cannot tolerate, which can lead to dehydration and other serious health consequences.

In general, signs of severe poisoning are associated with more dramatic physiological changes rather than mild or chronic symptoms. Other choices presented do depict various health concerns but do not align as closely with the recognized acute manifestations of pesticide toxicity. For instance, symptoms like headache, drowsiness, and dry skin are more commonly linked to mild toxicity or chronic exposure rather than severe reactions.