Vectors
Vectors
The most dangerous animals to humans are the vectors that transmit diseases. This section introduces the significance of vector species.
Learning Objective: Describe the impact of vectors on humans, including the life cycle and disease transmission capabilities of mosquito species.
A vector is an animal that can transmit an infectious pathogen, like viruses or bacteria, to humans. If a dog bit a human and incidentally transmitted the virus that causes rabies, then that dog would be a vector. However, the most common vectors are arthropods.
This video provides an overview of the significance of arthropod vectors.
Watch this video; you can select the closed captioning “cc” option if you would like to see the text.
Zoonotic diseases spread between animals and humans. Sometimes one species is the primary or “definitive” host, the body in which the pathogen reproduces. The pathogen may also live in intermediate hosts that can carry the pathogen to another primary host.
Toxoplasmosis is caused by Toxoplasma gondii (also called T. gondii), a protist (single-cell eukaryote) that can only reproduce sexually in the intestines of cat (felid) species, but can infect and proliferate asexually in other mammals, including humans. Humans primarily acquire the parasite by eating undercooked meat but can also acquire the parasite from an infected cat’s fecal material.
An estimated 30% of people worldwide and 20% of people in the Americas have at some point been infected with T. gondii. Most infected people do not show symptoms, and those people with symptoms experience flu-like muscle pain and swollen lymph nodes. Concerns have arisen related to infection in people with compromised immune systems and pregnant women. This is one of the reasons for why you may have seen global advertising against consuming undercooked meat.
Research is ongoing on whether infections from T. gondii impacts human mental health. People with blood antibodies against the parasite, indicating they had been or still are infected, have higher rates of some conditions, including schizophrenia and bipolar disorder. However, this is a common parasite in our species and further studies are needed to see whether there is actually a cause and effect relationship.
We’re taught when we are young to wash hands repeatedly; it’s a message worth repeating if you work around animals or have pets.
The next section introduces animals that live in billions of people’s bodies: intestinal worms.
Check your knowledge – Vectors
Review your notes. Can you describe the impact of vector species on humans? If so, move forward to the next page.
Learning Objective:
Describe the impact of vectors on humans, including the life cycle and disease transmission capabilities of mosquito species.
Go back to the Invasive Species Page
Go forward to the Intestinal Worms Page
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