fever, febrile illness

I come down with a fever.

私は熱病を患います

I come down with a severe fever.

私はひどい熱病を患います

I come down with a severe fever abroad.

私は海外でひどい熱病を患います

I come down with a severe fever abroad while traveling.

私は旅行中に海外でひどい熱病を患います

I come down with a severe fever abroad while traveling with my coworker.

私は同僚と旅行中に海外でひどい熱病を患います