Amenorrhoea is a symptom with many potential causes. Primary amenorrhoea (menstrual cycles never starting) may be caused by developmental problems such as the congenital absence of the uterus, failure of the ovary to receive or maintain egg cells. Also, delay in pubertal development will lead to primary amenorrhoea.
Diseases transmitted by mosquitoes include: malaria, dengue, West Nile virus, chikungunya, yellow fever, filariasis, Japanese encephalitis, Saint Louis encephalitis, Western equine encephalitis, Eastern equine encephalitis, Venezuelan equine encephalitis, La Crosse encephalitis and Zika fever.
Other mosquito-borne diseases include dengue fever, yellow fever, and encephalitis. There are more than 2,500 species of mosquito, and mosquitoes are found in every region of the world except Antarctica. During the peak breeding seasons, they outnumber every other animal on Earth, except termites and ants. They were responsible for tens of thousands of deaths during the construction of the Panama Canal.