This protects crops from pest infestations. Crop rotation can counteract high nematode infestations. Pubic lice infestations (pthiriasis) are usually spread through sexual contact. Propolis also contains persistent lipophilic acaricides, a natural pesticide that deters mite infestations. This eliminates infestations by narcissus fly and nematodes. Recent pine beetle infestations have threatened the forest. This in turn curbs infestations because immature insects cannot reproduce. Closed storage sheds and cabins are often ideal sites for rodent infestations. Ivermectin is a medication used to treat many types of parasite infestations. Synthetic pyrethroids are the main class of insecticides used to control triatominae infestations. These ingredients are mostly found in shampoos that are meant to fight against parasite infestations. This includes fur loss, parasite infestations, and weight loss. The American mink often carries light tick and flea infestations. Apiaries may suffer from a wide variety of diseases and infestations. Pesticides and sanitizing agents are available to use against these infestations.