Human Angiostrongyliasis Zhao-Rong Lun, Ph.D. School of Life Sciences SunYat-Sen University Guangzhou , China

Transcription

1 Human Angiostrongyliasis Zhao-Rong Lun, Ph.D. School of Life Sciences SunYat-Sen University Guangzhou , China 2011/8/23 1

2 Angiostrongyliasis caused by Angiostrongylus cantonensis An important food-borne parasitic disease; Cases reported globally; Mainly outbreak in tropical regions with the exception of imported cases (Beijing in 2006, more than 160 cases reported, snails were imported from one of the endemic regions: Guangxi); Main clinical manifestation: eosinophilic meningoencephalitis and meningitis. Fetal occurred. 2011/8/23 2

3 Founder of A. cantonensis Prof. Xin-Tao Chen (=H.T. Chen), (Chen, HT., A new pulmonary nematode of rats, Pulmonema cantonensis ng, nsp from Canton. Ann Parasitol 1935; 13: ) Dr. Chen discovered the rat lungworm (A. cantonensis) from a rat collected from Guangzhou in He also made a great contribution to the control of schistosomiasis in China. 2011/8/23 3

4 It is still a mysterious why this rat lungworm was mostly found in the brain and cerebral fluid although it could also be found from the lung of human? It may be one of the most important reasons which causing death in the nonnatural hosts. More studies should be done on the pathogenesis. 2011/8/23 4

5 Brain and lung are the most organs where the rat lungworm was found from the patients. However, optical angiostrongyliasis was also found in some cases. 2011/8/23 5

6 The life cycle of Angiostrongylus cantonensis The adult worms develop to sexual maturity and lay eggs at the pulmonary arteries (A). The eggs are hatched into first-stage larvae (the juveniles), which are swallowed and are excreted out with the feces (B). The larvae in feces are swallowed by intermediate host mollusks (snails or slugs) and develop into third-stage (infective) larvae (C). The third-stage larvae are then transmitted to the paratenic hosts such as shrimps, land crabs, predacious land planarians and monitor lizards (D). Humans occasionally acquire A. cantonensis when they eat snails, slugs and sometimes, land crabs, frogs, freshwater shrimps, monitor lizards, or vegetables, which contain the infective larvae (E). The larvae are digested from tissues and enter the bloodstream in intestine (F). The larvae finally reach the central nervous system (CNS) and cause eosinophilic meningitis (G) or move to the eye chamber and cause ocular angiostrongyliasis. (Adapted from Wang et al., 2008) 2011/8/23 6

7 Cases of angiostrongyliasis globally Human A. cantonensis infection has attracted increasing public attention worldwide due to outbreaks, and also because more and more sporadic cases are being reported in Western travelers in recent years. By 2008, over 2,800 cases of human angiostrongyliasis had been documented in more than 30 countries. However, there are, no doubt, many more cases, unreported due to lack of awareness of this parasite within the medical community. During the period , an additional 77 cases were reported (next slide). (from Wang QP et al., The Lancet Inf Dis., 2008, 8: ) 2011/8/23 7

8 Map of A. cantonensis distribution globally Distribution of A cantonensis and human A cantonensis infections or outbreaks worldwide. Endemic regions are those countries in which human cases of angiostrongyliasis or animal reservoirs of A cantonensis have been identifi ed. This is not intended to imply that A cantonensis is endemic throughout these entire countries. Conversely, those areas marked as nonendemic regions may well be countries where no investigation has taken place and so cannot be considered free from A cantonensis infection. (from Wang QP et al., The Lancet Inf Dis., 2008) 2011/8/23 8

9 Cases of human angiostrongyliasis reported worldwide since 2008 (Wang et al., 2011, Eur J Clin Microbiol Infect Dis, DOI /s ) Regions Cases References China 65 [17, 18] Thailand 8 [19, 20] India 1 [21] French 1 [22] Germany 1 [23] Jamaica 1 [24] 2011/8/23 9

10 The outbreaks of human angiostrongliasis have been reported in mainland China since 1997(Wang et al., 2011, Eur J Clin Microbiol Infect Dis, DOI /s ) Years Regions Cases References 1997 Zhejiang 65 [25] 1999 Heilongjiang 2 [26] 1999 Liaoning 3 [26] 2002 Fujian 29 [27-29] 2004 Zhejiang 3 [31] 2006 Beijing 160 [33] Guangdong 38 [17,34] Yunnan 92 [18,30,31] 2011/8/23 10

11 The distribution of A. cantonensis and its outbreaks in China. The endemic regions of A. cantonensis are marked as purple and the outbreaks of human A. cantonensis are marked as green triangle. Patients were infected with the rat lungworm by digested uncooked infected snails (from Wang QP et al., 2011) 2011/8/23 From Wang et al.,

12 Mammalian Hosts Rattus norvegicus Rattus rattus Rattus exulans 2011/8/23 12 From Wang et al., The Lancet Inf Dis., 2008

13 Mammalian Hosts Rattus rattus Rattus norvegicus Rattus exulans Rattus exulans distribution 2011/8/23 13

14 Snails Achatina fulica, (African giant snail) Pomacea canaliculata, (Apple snail), 1980 s, South China 2011/8/23 14

15 Acknowledgments Dr. Qiao-Ping Wang (SYSU, Guangzhou) DR. De-Hua Lai (SYSU, Guangzhou) Prof. Zhong-Dao Wu (SYSU, Guangzhou) Prof. Xiao-Guang Chen (SCMU,Guangzhou) Dr. Xing-Quan Zhu, Lanzhou Vet Med Inst, China Supported by the National Basic Research Program of China (973 program) (No#2010CB530000) 2011/8/23 15

16 2011/8/23 Lungworm workshop, Hawaii, August 16-19,