Links For more information, please contact your Regional Veterinarian, your local Department of Environment and Conservation Officer or the Health Conservation: Division. www.env.gov.nl.ca/env/ Parasites of

Canadian Cooperative Wildlife Health Center Caribou: Other information pamphlets are www.ccwhc.ca available online from the Department of Larvae Natural Resources at:

Photo Credits www.nr.gov.nl.ca/agric/ Infestations

(Figures 1-3)

Dr. Murray Lankester

Publication: DS 04-008 Last Revised: March 2010

Department of Natural Resources Animal Health Division P.O. Box 7400 St. John's, NL A1E 3Y5

t 709.729.6879 f 709.729.0055

[email protected] Introduction larvae’s life, they are about the size of a The infestation usually does no harm Throat Bots small grain of rice and are almost to them other than annoyance and is not trompe All wild carry diseases. In transparent. They may be seen on the considered to have any public health The second larvae of interest is some cases, these might be of concern if surface of the muscles or under the skin. significance. The hides of animals that have the throat or nose bot (Cephenemyia they can spread to or domestic been affected can often have 100's of ). Its life cycle starts with the animals. In other cases, they might be of Through the winter and into the holes or scars in them from the emerging female fly laying larvae on the face of interest if they impact on the health of spring, they continue their migration up to larvae and therefore have minimal value for the caribou around the nostrils. Unlike our wild herds, or simply because the the spine and rump of the animal where leather. the , in the case of the bot, signs of the disease have been noticed they cut a breathing hole through the skin. there is no egg laid, it is actually a and you want to know more. This infestation is not considered to larvae (maggot) that leaves the female.

This pamphlet is one of a series By early summer, the warbles are affect other animals. often have These larvae then crawl into the mouth produced on the common diseases of about 1 inch (2.5 cm) long and are ready to warble of their own, but these are of a and into the caribou’s nasal sinuses and caribou, and it covers the larval form of emerge from the back. They then fall to the different species. back of the throat where they spend the two different flies commonly seen in this ground and pupate. From the pupae winter. In heavy infections, there may be province. Neither of these are a cause of emerges the adult fly that only lives long well over 50 of these larvae occupying public health concern. enough to mate and lay its eggs on another these cavities. This can cause caribou. The adult lives such a short time suffocation of the animal in extreme cases, as well as varying degrees of Fly Larvae Infestations that it doesn’t even have mouth parts to feed. local reaction and pneumonia. Warbles and throat bots are common names for the larvae of two The growth and emergence of the In the spring, the larvae detach types of flies that can be found in the larvae and the buzzing of the adults around themselves from their host and leave carcasses of caribou in this province. the caribou as they try to lay their eggs can through the nostrils where they fall to Many people who hunt these animals be very annoying to the animal. At this time the ground. This can cause a lot of may be familiar with their appearance. of year, they may appear agitated and are Figure 2: Warble fly larvae emerging distress to the caribou, including sometimes seen jumping around to avoid from back. snorting and sneezing as they block and Warbles the irritation. irritate the nostrils. Once on the ground, the larvae pupate and develop into an Warbles are the larvae of the adult. In the fall, the adults again swarm warble fly (), which around the caribou to lay more larvae lays its eggs on the hair of the caribou’s on their faces. This swarming legs and lower body in mid-summer. accompanied by loud buzzing can be Once the eggs hatch, the larvae very disturbing to the caribou, causing (maggots) penetrate the skin of the them to run around and at times lose caribou and start a long migration condition if they stop feeding. towards the animal’s back.

Hunters may see signs of these migrating larvae in the fall when skinning Figure 1: Warble fly pupa and adult. Figure 3: Bots in the throat of a caribou. out an animal. At this early part of the