Sporadic cases of chikungunya have been reported since mid-February.

自2月中以来报告了基孔肯亚病的散在病例。

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In epidemiological terms, there is generally a background of sporadic cases, with occasional outbreaks.

从流行病学的角度来看，偶然暴发一般存在有散在病例的背景。

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Meningococcal disease is endemic in Delhi and sporadic cases of meningococcal meningitis have been occurring in Delhi in previous years.

脑膜炎球菌病在德里流行，并且在前几年德里一直发生脑膜炎球菌性脑膜炎的散在病例。

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The other 58 cases are sporadic cases with no clear connection to the three outbreaks.

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It does not normally infect humans, although sporadic cases do occur usually in people who have had close contact with pigs.

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Before 1996, sporadic cases of cyclospora infection turned up only in people who traveled in developing countries and in those with HIV or another condition causing immune-system compromise.

CNN: Cyclospora infection