Plague

presentation deals with the role of vector and animal resorvoir in transmission of plague.

1. ROLE OF VECTORS & ANIMAL Reservoir IN TRANSMISSION OF PLAGUE Presented by : ANIL KUMAR M.Sc. PHE II ND Sem VCRC(2015-17)

2. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE INTRODUCTION Plague is a zoonotic disease caused by highly virulent bacteria Yersinia pestis . Distribution of plague is worldwide maintained by wild rodents and their fleas in the natural foci and localized infection. Disease takes three main forms: Bubonic , S epticemic and Pneumonic . Untreated bubonic plague can lead to secondary pneumonic stage with 100% mortality. Plague has lead to three pandemics. Yersinia pestis bacteria can also be used as biological weapon. WHO identify plague as emerging disease.

3. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE HISTORY 540-750 AD : Justinian’s plague 50% - 60% people died of Rome along with the death of rats Fall of the Roman Empire 1346-1400 AD : Black Death pandemic Quarantine ~30 million European population died Fall of the feudal system 1660 : Great Plague of London 1865 : Third epidemic in China and India 12 million people died 1894 : Alexandre Yersin and Shibasaburo Kitasato independently find the plague bacterium in samples from humans and rats during the Hong Kong epidemic 1895 : Wild rodents are confirmed as hosts of plague when wild marmots in Mongolia and Russia are found infected. 1896 : Waldemar Haffkine develops a partially effective heat-killed vaccine and uses it during an outbreak in Bombay. 1897 : Yersin proposes a link between rats and plague 1905 : William Glenn Liston provides proof of fleas as the vector of plague . 1914 : Charles James Martin and William Bacot describe transmission of Y. pestis by rat fleas, Xenopsylla cheopis , with blocked foreguts.

4. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Taxonomical hierarchy of Yersinia KINGDOM : Eubacteria PHYLUM : Proteobacteria CLASS : Gammaproteobacteria ORDER : Enterobacteriales FAMILY : Enterobacteriaceae GENUS : Yersinia SPECIES : pestis , enterocolitica , pseudotuberclosis

5. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Characters of Yersinia pestis Gram –negative Non-motile Non spore forming Coccobacillus Size : 0.5-0.8 μ m(diameter) 1-3 μ m(long) Optimum temp: 28-30°C Optimum pH : 7.2-7.6 (extreme 5-9.6) Cell wall : lipopolysaccharide and enterobacterial antigen Obligate parasite By developmental mutational changes and gain of two plasmids from Y. pseudotuberclosis and its progenitor Y. enterocolitia it become more virulent and able to cause disease. Three biovars present : ribotype O/Antiqua, mediaevalis ribotype O and ribotype B/ Orientalis (based on their convesion of nitrate to nitrite and fermentation of glycerol)

6. DISTRIBUTION ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Group Number of species Rodents More than 200 Carnivores 20 Lagomorphs 14 Insectivores 4 Artiodactyla 3 Primates 2 Marsupials 2 Animals naturally infected with Y. pestis (Data represent relative number of species in each group and may not include all species ever found to have been infected : Poland and Barnes, 1979; Pollitzer,1954 )

7. Region Animal resorvoir Primary vector Common name Scientific name Common name Scientific name INDIA Indian gerbil Tatera indica Rat fleas Xenopsylla cheopis Rat Rattus rattus Gerbil fleas Xenopsylla astia Nosopsyllus punjabensis Bandicoot rat Bandicota bengalensis Bandicota indica Metad Millardia meltada Indian field mouse Mus booduga Spiny field mouse Mus platythrix Indian bush rat Golunda ellioti Palm squirrel Funambulus species ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Major wild rodents and flea vectors of natural foci * Sentinal animal :

8. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Indian gerbil Millardia meltada Rattus rattus Golunda ellioti

9. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE

10. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Cases and Deaths due to Human Plague in India Year Place Cases Deaths 1963 Throughout India 197 22 1964 Penninsular India 106 13 1965 -do- 1 1966 -do- 46 2 1967-1993 - Nil Nil 1994 Maharashtra/Gujarat 876 54 1995-2001 Nil Nil 2002 Simla Dist.Himachal Pradesh 16 4 2003 Nil Nil 2004 Uttar Kashi Dist.Uttarakhand 8 3 2005-2015 - Nil Nil

11. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Different routes of transmission of Y. Pestis to humans TRANSMISSION

12. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE

13. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Murine toxic( ymt ) : for enhancing the survival rate of Y. pestis (all gram negative) in fleas midgut . Pigmentation locus( Pgm ) : responsible for dense colonies of Y. pestis and its blockage in proventriculus and iron uptake. Hemin storage locus( Hms ) : it enables Y. pestis to synthesise biofilm which allows dense colony growth in proventriculus and resist it from going to the midgut .

14. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE TRANSMISSION CYCLE The Y. pestis transmission cycle and the progression from bubonic plague to pneumonic plague in humans. Y. pestis is transmitted between rodent hosts and flea vectors in two cycles: domestic and sylvatic. Humans can become infected by flea bites or by direct contact with infected rodents and other animals. Pneumonic plague can be transmitted person-to-person. Solid lines: common routes and dashes occassional routes.

15. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE EXAMPLE: Damaged grain storage or garbage will attract rodents and animals Domestic animals may be affected by infected fleas and may pass the infection to humans Rat fall indicate the epizootic of plague

16. ROLE OF VECTORS AND ANIMAL RESORVOIR IN TRANSMISSION OF PLAGUE Continued… Infected fleas jump to humans in search of bloodmeal . People will develop bubonic plague after bittten by infected flea Pnemonic plague spreads person-to-person through inhalation of infectious droplets

17. References : Plague by Rachel C. Abbott and Tonie E. Rocke , National Wildlife Health Centre, Circular 1372, US department of Interior and US department of geological survey,2012 Robert D. Perry and Jacqueline D. Fetherston , Yersinia pestis – Etiology Agent of plague, Clinical Microbiology Reviews, Jan. 1997, p. 35-66., Vol 10(1) Angela Clem and S Galwankar ., plague: A Decade Since the 1994 Outbreaks in India , JAPI, Vol. 53., May 2005 Plague, N. Balakrishnan ., National Centre for Disease Control