Veterinary Entomology

1. Veterinary Entomology Prof. Dr. Muhammad FiazQamar

2. VETERINARY ENTOMOLOGY 4(2-2) • THEORY General introduction of entomology, Arthropods and their economic significance, Classification of arthropoda, Respiratory and digestive systems of arthropods, Nervous and reproductive systems of arthropods, Different types of mouthparts of insects and arachnids and their significance in disease transmission, Haematopinidae; Linognathidae, Pediculidae and other species of lice, Cimicidae, Reduvidae, Redyvudaes, Pulicidaeand others, Culicidae, Ceratopogonidae and Simulidae, Psychodidae, Tabanidae, Gastrophilidae, Glossinidae, Muscidae, Calliphoridae, Oesteridae, Hypodermatidae, Cuterebridae, and Hippoboscidae, Ixodidae, Argasidae, Demodicidae, Sarcoptidae, Psoroptidae, Dermanyssilac and cheylotodae, Pathogens transmitted by insects and arachnids: A Review

3. BOOKS RECOMMENDED: • 1. Georgi, J. R., M. E. Georgi and V. J. Theodorises, 1999. Parasitology for Veterinarians. 7th Ed. W.B. Saunder Company London. • 2. Hayat C.S. and M. Akhtar, 1999. Parasitic Diagnosis, UGC. Govt. of Pakistan. • 3. Iqbal, Z., M. N. Khan and A. Jabbar 2003. An Illustrated Textbook of Veterinary Entomology. Friends Science Publishers, Faisalabad, Pakistan. • 4. Khan, M. N., Z. D. Sandhu, A. Jabbar and Z. Iqbal 2003. Manual of Veterinary Entomology. Friends Science Publishers, Faisalabad, Pakistan. • 5. Kettle, D.S., 1995. Medical and Veterinary Entomology. 2nd Ed., C.A.B. International, Wallingford Oxon UK. • 6. Soulsby, E. J. L., 2006. Helminths, Arthropods and Protozoa of Domesticated Animals. The English Language Book Society BailliereTindall, London. • 7. Wall, R. and D. Shearer, 1997.89 Veterinary Entomology. 1st Ed., Chapman & Hall

4. INTRODUCTION TO VETERINARY ENTOMOLOGY • Arthropods are one of the most remarkable creatures on the earth, and they merit study for at least two major reasons. • First, arthropods have unsurpassed diversity and niches; because of their extensive variation. These animals can provide an in-depth understanding of nature and the many ways that biological problems have been met. Arthropods fly, jump, hide, they see ultraviolet light, they produce and molt an extraordinary exoskeleton, and they posses’ magnificent colors and shapes. Few habitats exclude arthropods. In withstanding harsh environments, they are unparalleled. Some live in the arid deserts, some in hot springs up to 80Oc, others on mountain picks as high as 6096 meters, some in tropical rain forest, and there are arthropods that live in Arctic temperatures that reach below – 200c.

5. A second major reason is that knowledge of arthropods is essential as we manipulate eco-systems for increased food production and better health. Back in the early 1900s, many entomologists were concerned about the competition for food between human kind and arthropods, and some entomologists believed that arthropod control was imperative for survival of human race. Although such a position may seem some what extreme, arthropods do consume or spoil sufficient crops and products to feed many millions of people who starve each year. And arthropod/ insect –transmitted diseases, to humans, animals and crops, remain a threat to health and civilizations. As a result, it is good to understand “what arthropods are to the layman”. For example:

6. To some people arthropods are unpleasant creatures: crabs, spiders, beetles, caterpillars. • • To some people arthropods are fliers: mosquitoes, moth, bees, and wasps. • • To some others, arthropods are biters and stingers; bees, wasps, ants, termites, scorpions. • • To some arthropods are jumpers: fleas, crickets, grasshoppers, • • To some people arthropods are singers: crickets, cicadas… • • Arthropods to some others are sign of good luck: fly, June beetle, • • To others, they are sign of evil eyes: black beetle. • • To other people, arthropods are source of food; larvae, ants, grasshoppers, etc • • To some people, arthropods are medical agents: bees, beetles, scorpions, spiders. • The above are some of the thoughts of people who do not know the characteristics of arthropods and who had no chance to study entomology. Therefore it is worth to teach people the proper characteristics of arthropods by understanding entomology.

8. Mechanical disease transmission: disease agents are carried from one host to another by arthropods simply mechanically carried by the body parts (example wings, hairs, feces, vomitus, etc). In this type of disease transmission no change takes place in the number, form or developmental stages of the organism, but simply deposited in the body, food or drink of the host. • Biological disease transmission: the agent will exhibit changes in form and or number of developmental stages in the arthropod before entry to the host. This includes hereditary (transovarian) and transital transmissions: Propagative, cyclodevelopmental and cyclopropagative. • • Propagative: • In propagative type of disease transmission only the number of pathogens increases and the developmental stage remain constant. The diseases plague and typhus are good examples of propagative type of disease transmission. • • Cyclo-developmental: • In this type of disease transmission, only the developmental stage (form) of the disease pathogen is changed (small to big, immature to matured stage, etc.), while the number of the pathogenic organism remains constant. Example Filariasis • • Cyclo-propagative: • This type of disease transmission is a combination of both propagative and cyclo-developmental; whereby the disease pathogen undertakes a change both in number and developmental form (stage). Example Malaria.

9. • Trans ovarian/ Trans-stadial transmission: • It is a type of disease transmission, whereas the causative agent is transmitted to the immature stage (usually to the egg) from the adult insects and / or other arthropods which carry disease pathogens. When the infected egg completes its developmental stage; it becomes infective or can transmit the disease to man and other animals. Ticks and sand flies are very good examples of arthropods that exhibit hereditary disease transmission.

10. Existing public health problems • In tropical countries, the largest groups of illnesses are probably insect-borne. It is therefore, important to know the habits of the insect vectors and how they transmit diseases. It is difficult to implement control measures of insects, without some knowledge of entomology and specifically veterinary entomology. To this effect, this course is concerned with the study of arthropods (especially of insects) that are of Animal as well as public health importance. • Due to their occurrence in large numbers in domestic situations, the problems of arthropods include spoiling food and other materials by their feeding habits, causing nuisance and perhaps being involved in the transmission of infectious organisms. Others feed on domestic fabrics and structure of buildings, rendering them unusable or unsound. Moreover, a wide array of arthropods cause toxic reactions in vertebrates. • The cause of intoxication may be direct (bites, stings, defensive secretions) or indirect because of hypersensitivity (allergy).

11. Review questions • 1. Define entomology. • 2. Define Veterinary entomology. • 3. Discuss existing public health problems associated with arthropods. • 4. Explain the different disease transmission mechanisms by arthropods.