What is Rift Valley Fever?
Rift Valley Fever (RVF) is a disease-causing virus that mostly affects livestock, but can also infect humans. RVF was first identified in Kenya in 1931. It is primarily transmitted through contact with bodily fluids or tissues of infected animals or through vectors such as mosquitoes that have been in contact with infected animals. It causes the spontaneous death of unborn animals, and kills 90% of young animals that it infects. Humans who get the disease may experience no symptoms at all, or may experience flu-like symptoms such as fever as well as muscle and joint pain. These symptoms usually last from 2 - 4 days. A very small number of people infected have severe symptoms that affect the eyes or cause inflammation in the brain. RVF is primarily found in south and east Africa.
What is a pathogen?
A pathogen is a microorganism that causes a disease in living things. Humans have defenses against pathogens such as the immune system and helpful bacteria in the body, but if one of these is compromised by something such as antibiotic medicine, the pathogen can cause disease.
What is a vector?
In biology, a vector is an organism that does not cause a disease by itself, but carries the disease from an infected host to another organism, infecting this organism with the disease. The mosquito is the main vector of RVF, especially Aedes mosquitoes. The Aedes mosquito is know as a vertical vector because the dormant egg of this species can be infected with the virus and the disease can re-emerge even after years of dormancy when the mosquitoes emerge from their larval stage. Other mosquito species, such as Culex, are horizontal vectors since they can pass the virus from host to host, yet their dormant eggs do not support the virus and these species do not transmit the virus after initially emerging from their egg stage.
What is a population?
The population is the total number of organisms of a given species in a specific area. The change in population of an area is described by the following: current population + births + immigration - deaths - emigration.
What are biotic factors in an environment?
Biotic factors are the living organisms in a given environment that shape that environment. These include plants, animals, and algae.
What are abiotic factors in an environment?
Abiotic factors are non-living things that help shape the environment. These include temperature, amount of light, and availability of water.
What is the carrying capacity of an environment?
The carrying capacity of an environment is the maximum number of organisms of a given species that an area’s resources can support.
What is a vaccine?
A vaccine is a dead or weakened form of a pathogen that is introduced into the body to make the host more immune to the disease. The vaccination will not hurt the host, but it allows the immune system to be exposed to the pathogen so that it "remembers" how to destroy it if it ever encounters it again.
How does the human body fight pathogens?
The primary immune system defenders in the human body are white blood cells (leukocytes). These cells move throughout the blood vessels of the body searching for pathogens. White blood cells are categorized into two types: phagocytes and lymphocytes. Phagocytes remove pathogens by surrounding them and disposing of the invaders. Phagocytes include macrophages, neutrophils, monocytes, and mast cells. The function of lymphocytes is to recognize, stimulate other leucocytes to join in the attack (T-lymphocytes) and create antibodies to destroy the pathogens (B-lymphocytes).
Mosquito Database
Culex pipiens
)
Mosquito Life Cycle
Mosquitoes! Those buzzing, biting insects go through many changes before they land on your arm. It all starts with tiny eggs, laid on still water like puddles or ponds. These hatch into larvae, little wigglers that breathe through tubes at the water's surface. They munch on algae and other tiny things. After a few molts, they become pupae, kind of like comma-shaped cocoons. Inside, the pupa changes into an adult mosquito! Finally, it breaks free, ready to fly and (for females) seek a blood meal to lay her own eggs. The whole cycle takes about a month, and understanding it can help us control mosquito populations.
Rift Valley Fever in Sheep
Imagine a happy flock of sheep grazing in a field. But wait! A tiny mosquito lands on a sheep and bites it. This isn't your average itch. The mosquito might be carrying a hidden enemy called Rift Valley Fever, a nasty bug (virus) that can make sheep very sick.
This fever spreads through mosquito bites, and sheep are especially vulnerable. When infected, they might lose their appetite, feel weak, and even have trouble having lambs (baby sheep). In really bad cases, they can even die. Rift Valley Fever can be a big problem for farmers, because sick sheep can't produce wool or milk as well, and losing lambs means a smaller flock.
But how do these tiny mosquitoes become infected in the first place? It all starts with rain. When there's a lot of rain, it creates puddles and swamps. These are like mozzie motels for mosquitoes – perfect places for them to lay their eggs and hatch new little biters. The trouble is, some wild animals, like buffalo and camels, can also carry Rift Valley Fever. When infected mosquitoes bite these animals, they pick up the virus and then spread it to healthy sheep, starting the cycle all over again.
So, what can we do to protect our fluffy friends? Farmers can vaccinate their sheep to help them fight off the fever. They can also try to control the mosquito population by getting rid of stagnant water where they breed. This can be done by draining puddles, keeping gutters clean, and even introducing special fish that eat mosquito larvae! By working together, farmers and scientists can help keep sheep herds healthy and happy.
What is a flock?
A flock is like a big group of animals that usually stick together. It's most commonly used for birds and sheep! Imagine a bunch of fluffy sheep grazing in a field together, that's a flock! Or picture a swirling mass of birds flying in the sky, that's also a flock.
Flock can also be used for a large group of people, like a flock of tourists rushing to see a famous landmark.
Rift Valley Fever (RVF) is a disease caused by a common pathogen. The fever can infect livestock and human populations. Once infected, the livestock can then pass this deadly disease to other animals, quickly infecting an entire herd. Your challenge is to determine the cause of RVF and to identify the organism that moves the disease from infected to healthy animals.
