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.
Mosquitoes alone spread malaria in nature. (The disease can be transmitted unnaturally through shared needles or by blood transfusion from infected donors.) When a mosquito bites an infected individual, the sporozoan's male and female sexual stages, or gametocytes, are taken up in the blood meal.