|Description:||Using a pin as a reference tool, this photograph depicts a dorsal view of four Amblyomma maculatum ticks. From left to right, this group of four included a larval tick, a nymph, an adult male, and at far right, an adult female. Note that the head of the pin measures just under 2mm in diameter, while its full length measures 22mm.|
This tick specie is a known vector for Rickettsial organisms, Rickettsia parkeri, and Ehrlichia ruminantium, formerly Cowdria ruminantium. R. parkeri is a member of the spotted fever group of rickettsial diseases affecting humans, while E. ruminantium causes “heartwater disease”, an infectious, noncontagious, tick-borne disease of domestic and wild ruminants, including cattle, sheep, goats, antelope, and buffalo. Each life stage depicted here, can feed on human hosts, and can be infected with Rickettsia parkeri.
Note the considerably-larger scutum, or “shield” covering this male’s entire dorsal abdomen, unlike its female counterpart, an example of which can be seen in PHIL 10875, and 10876, which sports a scutum covering only a small caudad section of her dorsal abdomen just behind her head. The smaller scutum in the female enables its abdomen to expand considerably, leading to an engorged appearance after ingesting its host blood meal. Ticks possess four pairs of legs, placing it in the class of Arachnida, as its cousins, the spiders and scorpions.