Xenopsylla cheopis and plague

1. Xenopsyllacheopisand plague Maureen Ndambuki EvalyneNjeri VeranjaLiyanarachchi

2. Morphology • Has head, thorax and abdomen • 1mm-4mm long • Has piercing/sucking mouthparts • Has 4 stages • Egg • Larva-no eyes or legs • Pupa-free living • Adult-6 legs

3. Taxonomy Xenopsyllacheopis Kingdom - Animalia Phylum - Arthropoda Class - Insecta Order – Siphonaptera Superfamily – Pulicoidea Family - Pulicidae Genus – Xenopsylla Species - cheopis

4. Geographical Range Is found worldwide usually in tropical regions

5. Hosts • Definitive Hosts: • Rodents, Primates and occasionally humans • But brown rat is the most common definitive host • Intermediate Hosts: • No known intermediate hosts

6. Facts GEOGRAPHY: Worldwide or anywhere where rats are present It’s a flea also known as the “oriental rat flea” or the “Tropical rat flea” Zoonotic disease It’s a vector for the murine typhus (rickettsia typhi) and Bubonic plague(Yersinia pestis)that made history and swept though Europe in the 14th century It’s the primary vector for plagues in plague endemic areas like Asia, Africa and S. America

7. Adult male and female fleas feed on the blood of their particular host species or group of host species - they are known as obligate ectoparasites. However, without the specific host, fleas will commonly bite other warm-blooded animals. The larvae (also known as grubs and maggots) are not usually parasitic, but are scavengers feeding on organic matter that they find in the nest or dwelling place of the host. A female flea can produce about 25 eggs a day for at least 3–4 weeks. Most eggs are laid in the host animal's nest or regular sleeping place. They are about half a millimeter in length, white and difficult to see with the naked eye unless they are laid on a contrasting surface. The life expectancy of a flea varies. It is usually 2–3 months, but may be up to 1.5 years, depending on factors including suitable temperature, food supply and humidity. Most animals carry a few fleas with them at all times. It is only when this number dramatically increases that the fleas can become a biting nuisance to both animals and humans.

8. As a vector Fleas like to feed on blood at body temperature. When infected rats die, the infected fleas leave to look for a new host. This might be another rat, or a human. As the flea feeds on its human host, a few bacteria pass into the bloodstream. The bacterium blocks the flea’s digestive system and causes the flea to continue biting and trying to feed. Eventually the flea dies of starvation but not before it has successfully transmitted the plague bacterium to multiple people.

9. Yersinia pestisinfection • A zoonotic bacterial infection caused by small rodents and their fleas but through flea bites can infect humans • Can take three forms • Pneumonic-through breathing, more virulent • Septicemic-infected blood • Bubonic plague-formation of buboes, most notorious form • The plague outbreak led to the outbreak known as the “Black Death” that made history as one of the most notorious disease episodes in history that changed religious, socio-economic, political and other forms of human civilization. Killed 30-60% of Europe’s population. • The bubonic plague is also believed to cause the “plague of Justinian” in 542 AD that affected the Byzantine Roman Empire and killed and estimate of 25 million people around the world.

10. Plague symptoms Fever Vomiting Dry coughs with thick mucus (pneumonic) Egg or apple shaped painful buboes-(bubonic) Internal bleeding leading to tissue necrosis (gangrene)-(septicemic)

11. Disease led to gangrene or blackening of various body parts and also swollen purple lymph nodes (buboes)

12. Life cycle

13. Life cycle summary Females oviposit eggs while in the host and since eggs are not sticky they drop off the hosts body Under favorable conditions the eggs hatch within 2-21 days and molt 3 times in 9-15 days The larvae then pupate in a week and then become adults Adult fleas can survive in high humidity for 38 days with no food. Means they can survive for long without hosts.

14. Transmission Poor sanitation, overcrowding and high numbers of rodents are conditions that enhance urban plague transmission. Large rodent infestations. The plagues spread real quick across countries due to the fleas carried by black rats that were passengers on merchant ships that sailed across continents Also spread due to migration by people from infected areas who spread the disease.

15. Pathogenesis • Inflammation • Small, red bumps that are very itchy • A rash can occur • Skin infection occurs due to severe itching

16. Treatment &Control Methods • Keep floors clean by vacuuming regularly to clear away all eggs, larvae and pupae • Use of repellents to avoid flea bite • Control of host animals such as eliminating rodentsand fleas • Keep pets in god hygiene • Avoid keeping disused articles • Spraying of insecticides to reduce the number of adult and larval fleas and as a supplement to the environmental control measures. • Antibiotics like streptomycin are effective against plague.

17. To see the depiction of what happened watch “ Black death movie, 2010” http://www.imdb.com/title/tt1181791/ Plague documentary http://documentaryheaven.com/the-black-death/

18. Review What are the definitive and intermediate hosts? What is the diagnostic stage in the life cycle? What disease does xenopsyllacheopis and plague cause? Where is the parasite found?