Arthropod vector

Rickettsia are more difficult to produce in quantity than bacteria. Similar to viruses, they are strict obligate parasites and require living cells for growth. They cannot survive long outside a host. They also have a selective affinity for specific types of cells in the body. They are normally transmitted by an arthropod vector (i.e., ticks, lice, fleas, mites), which also serves as either the primary or intermediate host. 

Anon. (1984), Chemical Methods far the Control of Arthropod Vectors amt Pests oj Public Health importance. WHO, Geneva. 

Disease Potential as Bioterrorism Agent (None/Low/Moderate/ High—CDC Category) Naturally Exists as Zoonosis (Yes/No) Transmission bi Arthropod Vectors (Yes/No)... 

Arthropod vector The phylum of arthropods includes insects, arachnids, and crustaceans. An arthropod vector is an arthropod, such as a mosquito, that transports pathogens from one host to another. 

Biological Weapon - An item of material that projects, disperses, or disseminates a biological agent including arthropod vectors. Blepharospasm - Uncontrollable winking caused by involuntary contraction of an eyelid muscle. BLPS - Ballistic / Laser Eye protection. Bradycardia - Abnormally slow heartbeat. Broken Arrows - An accident involving nuclear weapons. While it is almost impossible for the warhead to accidentally detonate, the accident may spread radioactive contamination over a wide area. 

The patient must be protected from potential arthropod vectors windows should be screened and/or closed. 

A cutaneous ulcer occurs in approximately 60% of patients and is the most common sign of tularemia. Ulcers are generally single lesions of 0.4 to 3.0 cm in diameter, with heaped-up edges (Figure 24-1). Lesions associated with infection acquired from mammalian vectors are usually located on the upper extremities, whereas lesions associated with infection acquired from arthropod vectors are usually located on the lower extremities. Ulcerative lesions are almost always accompanied by regional lymphadenopathy.13... 

Very little is known about the natural history of any of the filoviruses. Animal reservoirs and arthropod vectors have been aggressively sought without success. 

Viruses associated with most VHFs are zoonotic. This means that these viruses naturally reside in an animal reservoir host or arthropod vector. They are totally dependent on their hosts tor replication and overall survival. For the most part, rodents and arthropods are the main reservoirs for viruses causing VHFs. House mouse, and other field rodents are examples of reservoir hosts. Arthropod ticks and mosquitoes serve as vectors for some of the illnesses. However, the hosts of some viruses remain unknown - Ebola and Marburg viruses are well-known examples. 

For hemorrhagic fever viruses spread by arthropod vectors, prevention efforts often focus on community-wide insect and arthropod control. In addition, people are encouraged to use insect repellant, proper clothing, bednets, window screens, and other insect barriers to avoid being bitten. 

Alexander, C.J., Easterday, W.R., Van Ert, M.N., Wagner, D.M. and Keim, P. (2004) High-throughput extraction of arthropod vector and pathogen DNA using bead milling. Biotechniques 37, 730-734. 

Nansimhan S, Sukumaran B, Bozd< an U ec al. A tick andaxidaiit facilitates the Lyme disease agents sue-cesfiil migration from the mammalian host to the arthropod vector Cell Host Microbe 2007 2 7 18. 

Pathogen transmission can be blocked by immnnity to the arthropod vector... 

Military personnel deployed in the field often suffer more casualties due to endemic vector-borne disease than to engagement with enemy combatants. The most dangerous of these are carried (vectored) by biting arthropod vectors mostly of the bloodsucking variety. Among the diseases encountered by soldiers are malaria, dengue fever and yellow fever, carried by certain mosquito species encephalitis and Lyme disease, carried by certain ticks and leishmaniasis, carried by some species of sand flies (Fig 14.1). 

Figure 14.1 Arthropod vector of disease sand flies carry Lieshmaniasis. A black and tvhite version of this figure tvill appear in some formats. For the colour version, please refer to the plate section.

A, A-Diethyl-3-methylbenzamide (deet) has been regarded as the standard mosquito repellent for the past several decades. However, as a repellent for human use deet is not equally effective against all insects and arthropod vectors of diseases. - In most formulations, it has a short duration of action (not more than several hours) and several disagreeable cosmetic effects, such as an unpleasant odor. Of greater concern is the fact that when it is used in higher concentrations the deeper skin penetration can cause potential toxicity. In addition, deet is a plasticizer that reacts with certain plastics and synthetic rubber. ... 

P. F. Mattingly. The evolution of parasite-arthropod vector systems. In The Evolution of Parasite-Arthropod Vector Systems. A. E. R. Taylor (Ed.), Oxford, Blackwell, 1965. 

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