Nghiên cứu bệnh gạo lợn do ấu trùng cysticercus cellulosae gây ra tại tỉnh tỉnh sơn la, điện biên và biện pháp phòng chống tt tiếng anh

MINISTRY OF EDUCATION AND TRAINING THAI NGUYEN UNIVERSITY PhD CANDIDATE: DO THI LAN PHUONG STUDY ON CYTICERCOSIS IN PIGS CAUSED BY CYSTICERCUS CELLULOSAE LARVAE IN SON LA, DIEN BIEN PROVINCE AND ITS PREVENTIVE, CONTROL MEASURES Speciality: Veterinary parasitology and microbiology Code: 9.64.01.04 SUMMARY OF DISSERTATION IN VETERINARY MEDICINE Thai Nguyen, 2020 The dissertation was completed at: COLLEGE OF AGRICULTURE AND FORESTRY THAI NGUYEN UNIVERSITY Supervisers: Professor Doctor Nguyen Thi Kim Lan Associate Professor Doctor Nguyen Thi Ngan Reviewer 1: Reviewer 2: Reviewer 3: The dissertation will be defended at the Dissertation committee inNational level COLLEGE OF AGRICULTURE AND FORESTRY - TNU Time date month year 2020 The dissertation can be found at: - National Libarary; - Learning Resource Center - Thai Nguyen University; - Libraty of College of agriculture and forestry - TNU LIST OF PAPERS PUBLISHED RELATING TO DISSERTATION Do Thi Lan Phuong, Nguyen Thi Kim Lan, Nguyen Thi Ngan (2019), "The situation of porcine cysticercosis in some districts of Dien Bien Province", Journal of Science and Technology, Thai Nguyen university, 202 (9): 23 - 28 Nguyen Thi Kim Lan, Do Thi Lan Phuong, Phan Thi Hong Phuc, Nguyen Thi Ngan, Pham Dieu Thuy (2018), "Study of Cysticercus cellulosae infection in pigs in Son La province", Journal of veterinary Science, XXV(5): 56 - 64 Nguyen Thi Kim Lan, Do Thi Lan Phuong, Phan Thi Hong Phuc, Pham Dieu Thuy, Đao Van Cuong (2018), “A Study on the Prevalence of Cysticercus cellulosae in pig of Son La Province, Viet Nam”, Saudi J Med Pharm Sci (5), pp 587 - 591 INTRODUCTION Urgency of the dissertation Porcine Cysticercosis is caused by Cysticercus cellulosae (Taenia solium) larvae The disease is a zoonosis In Vietnam, C cellulosae is found in almost all provinces and cities nationwide, especially in the Northern mountainous provinces The average prevalence of pigs infected with C cellulosae in the North of Vietnam is from 1.0 - 7.2%, in the South is 4.3% (De N.V., 2004, De N.V and Le T H 2010) When pigs are infected, C cellulosae significantly cause harm to the health of pigs Most infected pigs are stunted and grow slowly In case the larvae parasitize the brain, the pig will show neurological symptoms, such as ataxia If the larvae parasitize in the tongue, paralysis of the tongue and jaw may occur (Nguyen Thi Kim Lan et al., 1999, Pham Sy Lang and Phan Dich Lan, 2011) The Adult tapeworms reside in human small intestine In addition to suffering from disease caused by adult tapeworm, people also are infected with taenia solium larvae (C cellulosae) parasitize in different places in the human body: muscles, eyes, heart, brain The most dangerous disease is neurocysticercosis - a disease that causes convulsions, hypersalivation, coma and death In recent years, pig farming has developed in all provinces and cities throughout the country However, many households in mountainous areas still raise pigs on a small scale, many households still have no toilets In addition, the control of pig slaughter in many local places has not been strictly implemented, and the inspection and detection of people infected with tapeworm have not been conducted thoroughly so that the disease still occurs in many places throughout the country, especially in mountainous provinces, including Son La and Dien Bien According to many authors, porcine Cysticercosis is difficult to recognize, diagnosis of the disease in animals is difficult because the symptoms are atypical, the disease causes economic losses The disease is dangerous because it can be transmitted to people The problems mentioned above reveal that study on porcine cysticercosis and effective preventive measures for this disease in Son La and Dien Bien provinces are very necessary Objectives of the dissertation Identifying characteristics of porcine cysticercosis caused by C cellulosae in Son La and Dien Bien provinces, determining the risk of pigs infected with cysticercosis caused by C cellulosae depending on pig farming practices in Son La and Dien Bien provinces Recommendation of preventive measures for porcine cysticercosis, thereby preventing human Taeniasis and cysticercosis The results of the project have made contribution to change the awareness, life and farming methods of people in the Northwest mountainous areas Scientific and practial significance of the dissertation 3.1 Scientific significance The results of the project are scientific information of the epidemiological characteristics of porcine cysticercosis in Son La and Dien Bien provinces, Data from pathological and clinical characteristics of the disease, effective preventive measures for the disease, and developing epidemiological map of the díease occuring have some new contributions to the science 3.2 Practical significance The results of the project are the scientific basis for recommendation to pig producer to apply the preventive measures for porcine cysticercosis in order to limit the prevalence of the disease, making contribution to development of pig heards and reduce the risk of pigs infected with adult tapeworm and tapeworm larvae in humans New contribution of the dissertation - The project is a systematic study on epidemiological, pathological and clinical characteristics of porcine cysticercosis in Son La and Dien Bien provinces - Recommendation of effective measures for prevention of porcine cysticercosis Prevention and treatment interventions of porcine cysticercosis have been recommended and applied widely in pig farming households in the provinces of Son La, Dien Bien and other provinces - Developing epidemiological maps for porcine cysticercosis occuring in Son La and Dien Bien provinces Structure of dissertation The dissertation consisting of 110 pages are divided into chapters: introduction (3 pages); Chapter 1: review of documents (32 pages); Chapter 2: Materials, contents and methods of study (18 pages); Chapter 3: Study results and discussion: (53 pages); Conclusions and recommendations (3 pages) References (12 pages); Pictures related to the project (17 pages); Appendix (26 pages) The dissertation includes 36 tables, 15 charts and graphs, maps, 88 colour pictures showing the results of the project, 132 references (50 documents in Vietnamese, 82 documents in foreign languages, in which 30.30% are documents from 2015 - 2019) Chapter REVIEW OF LITERATURE The life cycle of T solium is complex Humans are the only definitive host of T solium, humans and pigs also both play a role of intermediate hosts Pigs are infected with C cellulosae by eating food, drinking water containing either T solium scoleces or eggs pass in human faeces contaminated with tapeworms (Bouteille B., 2004; Satyaprakash K., 2018) C cellulosae can parasitize anywhere in pig or human body, such as: connective tissues, fat tissues, neck muscle, buttock, heart muscle, intercostal muscle, tongue muscle, brain, eyes and rarely found in parenchymal organs In severe infection,The larvae may also be found in parenchymal organs of host body (Pham Van Khue and Phan Luc, 1996; Chu Thi Thom et al., 2006; Phan Luc, 2006) When pigs were lightly infected with C cellulosae their clinical manifestation are rarely observed, pigs appear to be normally healthy (Trevisan C et al., 2016) Disection of infected pigs it parasitic larvae are often found in Skeletal muscle tissues with blocked capillaries resulting in obstructed circulation, hematoma; Nerve compression leading to paralysis The larvae also cause foci of fibromyositis and tissue inflammation in parasitic sites (Nguyen Thi Kim Lan, 2012) Diagnosis of C cellulosae in pigs cannot only be based on clinical symptoms, because the symptoms of infecction is atypical In order to correctly diagnose cysticercosis in pigs, it is necessary to perform dissection to search parasitic larvae in the muscles of pigs It can also be diagnosed by serological method (Nguyen Thi Kim Lan et al, 2008; Pham Sy Lang and Phan Dich Lan, 2011, Ana-Maria Oleleu et al., 2016) In order to prevent porcine cysticercosis in pigs raised in the east, south and west of Zambia, it is necessary to limit construction of latrine temporarily for humans, because pigs can easily access to human feces and infected with C cellulosae (Sikasunge CS et al., 2008) In addition, raising pigs in confinement and building pigpens away from the residental areas is an effective way for prevention of porcine cysticercosis (Zirintunda G and Ekou J., 2015; Madinga J et al ., 2017) Strengthening control of slaughtering pigs at slaughterhouses Pigs infected with C cellulosae must be removed and their meat must not be used as human food (Le Bach Quang, 2008; Meester M 2019) According to Pham Sy Lang and Phan Dich Lan (2011), when pigs are found to be infected with cysticercosis, they must be treated immediately and under the supervision of veterinary agencies to avoid using meat indiscrimately and transmitting the disease to humans If treated, two drugs for treatment of the disease can be administered at following dosage: albendazole: 30 mg/kg B.W and oxfendazole: 30 mg/kg B.W.These drugs can be administered in pigs for consecutive days, after 24 days the larvae will die (Zirintunda G and Ekou J 2015) Chapter MATERIALS, CONTENTS AND METHODOLOGY 2.1 Object, time and place of study 2.1.1 Objects - Pigs at different ages raised at household farm in districts of Son La and Dien Bien provinces -Cysticercus cellulosae (T solium) larvae (causing cysticercosis) in pigs 2.1.2 Place and time of study * Study period: 2016 - 2019 * Place of study: - Sampling places: districts of Son La province (Bac Yen, Muong La, Mai Son) and districts of Dien Bien Province (Muong Ang, Tua Chua, Nam Po) - Places for testing blood samples: Laboratory of Thai Nguyen University of Agriculture and Forestry, Institute of Biotechnology, Institute of Life Sciences of Thai Nguyen University, National Institute of Malariology Parasitology and Entomology, Thai Nguyen Central General Hospital 2.2 Materials of study 2.2.1 Animals used for the study and Study samples * Animals used for the study: - Pigs at different ages raised at household farms in Son La and Dien Bien provinces (used for determining the prevalence of C cellulosae infection) - F1 pigs (Landrace x Mong Cai), months old, healthy, weighing 17 - 18 kg / pig: 41 pigs (of which 21 were used to design experiments in study of pathological and clinical characteristics; 20 pigs of which were used for experimental drugs in treating cysticercosis) All of the experimental pigs were born from healthy mother pigs, raised in an environment that ensures veterinary hygiene, fully being fed with synthetic feed; piglets born were managed, reared and kept in hygienic condition strictly, serological test results using ELISA Taenia solium Kit showed negative Samples studied: T solium samples; blood samples from pigs experimentally infected with cysticercosis and blood samples from healthy pigs; Samples from Heart, liver, lungs, samples from healthy pigs respectively 2.2.2 Instruments, equipment and chemicals Automated DNA sequencer, microtome used to section paraffin and plastic embedded tissues; Celltac F hematology analyzer; AU480 chemistry analyzer used in biochemical test; refrigerator; light microscope, magnifying glass ; Test Kit SciMedx ELISA Taenia Solium / USA; chemicals for histology, Hematoxylin and eosin stain (often H&E stain), one of the principal tissue stains used in histology, alcool 70o, alcool 90o and other chemicals and laboratory equipment 2.3 Contents of study 2.3.1 Study on some epidemiological characteristics of porcine cysticercosis caused by Cysticercus cellulosae in Son La and Dien Bien provinces - The present situation of T solium infection in humans and C cellulosae in pigs in some districts of Son La and Dien Bien provinces - Comparison of the risk of pigs infected with cysticercus linked to farming practices of people in Son La and Dien Bien provinces - Compared the risk of people infected with T solium by eating habits in Son La and Dien Bien - Determining the correlation between the prevalence of T solium in humans and the prevalence of C cellulosae in pigs in Son La and Dien Bien provinces 2.3.2 Study on cysticercosis in experimentally infected pigs - Identifying cestode species - Infecting pigs with T solium eggs - Monitoring clinical symptoms in pigs infected with cysticercosis - Studying changes in some red blood cell indices in pigs, white blood cell indices and blood biochemical ndices in infected pigs - Determining the macropic and micropic lesions in pigs with cysticercosis 2.3.3 Study on some prevention and treatment interventions of cysticercosis in pigs - Determining time period of C cellulosae death - Using experimental drugs in treating cysticercosis in pig experimentally infected - Developing epidemiological maps of cysticercosis occuring in pigs in Son La and Dien Bien provinces 2.4 Studied methods 2.4.1 Method of determining epidemiological characteristics of cysticercosis in Son La and Dien Bien provinces 2.4.1.1 Methods of epidemiological study - Using descriptive epidemiological methods, analytical epidemiological and experimental epidemiological methods (Nguyen Nhu Thanh, 2011) * Sample collection: 2,078 pigs were dissected in Son La and Dien Bien provinces; districts in each province; communes in each district In each commune, dissected pigs were randomly examinated * Methods for determining relative risk (Relative Risk - RR): Determining the risk of the disease by calculating the relative risk (RR) according to Nguyen Nhu Thanh (2011) 2.4.1.2 Methods of identifying pigs with cysticercosis and collecting samples - Applying the complete helminthological dissection methods of K.I Skrjabin (1928) for examining pigs' muscles, heart, brain, kidneys, liver, spleen for detection of C cellulosae - The prevalence of the larvae was determined on the basis of identifying infected pigs out of 2,078 pigs examined - The intensity of larval infection was determined by the number of parasitic larvae 40 cm2 of muscle slices of pigs (based on Circular No 09/2016/TT - Ministry of Agriculture and Rural Development dated June 1, 2016), particularly in brain, kidneys and heart: the intensity of infection was calculated by the number of C cellulosae larvae present in the whole brain, kidneys, heart of each pig 2.4.1.3 Method of identification of Taenia solium Based on the identification key of Nguyen Thi Ky (1994) to preliminarily identify species of 10 tapeworm samples collected from infected people (based on morphology, structure of tapeworm scoleces and proglottids on the carmine stained smear) Thereby cestode identified in of 1o samples was T solium species Next, samples of tapeworms (designated as SL1, SL2, SL3, DB1, DB2, DB3) were preliminarily identified as T.solium species mentioned above which was further examinated using molecular techniques to confirm correctly that T solium species 2.4.1.6 Method of investigating some Livestock Production Practices, People’s living activities and tapeworm infection in Son La and Dien Bien Interviewing and recording questionaire of households in the study area, combined with local health organizations to identify people infected with T solium Summarzing questionnaires and finding collected from local health organizations 2.4.2 Study on cysticercosis caused by Cysticercus cellulosae in pigs 2.4.2.1 Method of infecting Taenia solium eggs in pigs Experimental pigs were divided into groups, including infected groups and control group, pigs in a group In experimental group I: Each were infected orally with 100,000 T solium eggs; group II pigs with 150,000 eggs Using ml plastic syringe to take 0.9% saline solution containing T solium eggs to, pump into the mouth of pigs so that they could ingest the eggs The control group consisted of pigs that only were given ỏally amount of ml of saline solution equivalent to that of the experimal groups 2.4.2.2 Method of studying the time period to complete the larval development stage (Cysticercus cellulosae ) in infected pigs After T solium eggs were given orally to pigs, pigs in each experimental group and control group were kept in confinement in pig pens One pig in each group was dissected at 15, 30, 45, 60, 75, 90 and 120 days to examine lesions and detect C cellulosae, monitoring the completion time of larval development stage in the muscles of infected pigs 2.4.2.3 Method of Studying on changing some hematological parameters and some bloodbiochemical indices in pigs experimentally infected with cysticercosis - Blood sampling: each blood sample was collected from each pig: Regarding experimentally infected pigs: from day 45 after infection, blood samples of all pigs surviving were collected at the time of dissection to determine changes in some physiological and biochemical indices of pigs' blood Specifically: 10 blood samples from 10 infected pigs were taken on day 45; blood samples on day 60; blood samples on day 75; blood samples on day 90 and blood samples on day 120 after infection (total of 30 blood samples) From the control group: pig blood samples were collected on day 45 after infection; blood samples on day 60; blood samples on day 75; blood samples on day 90 and blood sample on day120 (total of 15 samples) Blood samples were tested on the same day - Method of Blood tests: several RBC indices, leukocyte indices and some blood biochemical indices were analyzed on Celltac F hematology analyzer and AU480 chemistry analyzer 2.4.2.4 Methods of indentìying clinical features, macropic and micropic lesions in infected pigs - Clinical symptoms were identified by observing the clinical manifestations of 14 infected pigs (state body, eating, skin and mucous membranes, movement, faeces, body temperature, etc.), comparied of expression of infected pigs to control pigs - Macropic lessions: Each pig was dissected on day 15, 30, 45, 60, 75, 90 and 120 after infection C cellulosae that parasitize muscles and other organs in the body was serched Lessions were observed with the naked eye and magnifiying glass, typical lesions were taken picture of Compared to control pigs dissected at the same time to findthe differences between affected pigs and healthy pigs - Microscopic lesions: Studying microscopic lesions using method of preparing smears from paraffin-embedded tissue of Robert (1969), Burn (1974), stained with Hematoxilin - Eosin the results were readed under a light microscope and photograph taken Study on prevention and treatment interventions of porcine cysticercosis 2.4.3.1 Study of the viability of Cysticercus cellulosae experiments were conducted, the experiments were performed using meat samples from 14 pigs experimentally infected with cysticercosis * Determine the time period of C cellulosae death in the outside in summer and winter (stage 1: summer, stage 2: winter) Each experimental time included batches of 120 larvae (placed in petri dishes, each of which included 30 larvae) In summer: at each time 1, 2, 3, hours later; In Winter: At 1, 2, 3, and hours later the larvae were examined in a petri dish to find if the larvae survived or died Method of examination: Placing larvae in petri dish containing bile solution from bovine (80%) mixed with saline (20%), kept in incubator 39 - 40 oC for 15 minutes As a result the outer membrane of the larvae was decomposed to release tapeworm scoleces, if the tapeworm scoleces were found impossible moving, the larvae were dead From that, we could determine the time period of larvae death in the outside (Nguyen Thi Kim Lan, 2012) * Determine the time period of C cellulosae death in meat when treated with high temperature (boiled meat) The meat was cut into slices of cm thick and 15 slices of cm thick , weighing 1.5 - kg Meat was heated untial boiling and examinated whether larvae were killed or survived from the time the broth began to boil (30, 45 and 60 minutes for meat slices of cm thick; 45, 60, 75, 90 and 105 minutes for meat slices of cm thick) Each of time rate mentioned above, meat slices were treated (8 time rates time for treating 24 meat slices) Method of examination: After boiling with each time rate mentioned above, the meat slces were removed, the larvae deep in the meat slices were isolated to find whether the larvae survived or died according to the method mentioned above * Determining time period of killing C cellulosa by storing meat at a low temperature of -15oC Two experimental groups were designed, one of which consisted of 12 meat slices of pigs experimentally infected with cysticercosis, each slice with cm thickness; another group consisted of twelve cm thick slices; The weight of each sample was about 1.5 - kg The meat slices were placed in the refrigerator, the temperature was adjusted to -15oC This temperature was maintained for 2, 3, and days After each time mentioned above, meat slices were taken from each experimental group, the larvae deep in each meat slice were isolated to examine by the above method, if the scoleces did not move, the larvae were dead From this, the time needed to kill all larvae in meat was determined at a temperature of -15°C * Studying the vitality of larvae in smoked meat - Monitoring the larval survival time using method of hanging meat up the kitchent from the Thai family - Lean pork was cut lengthwise into slices of cm thick, 20 - 25 cm long Pork was put into pots and 4%, salted and mixed for about 25 - 30 minutes for salt infusion 11 Gavidia C.M et al (2013) reported that the prevalence of C cellulosae increased with the pigs age Adult pigs were infected more severely than younger ones Our study results were similar to those of the authors mentioned above 3.1.1.3 The prevalence of Cysticercus cellulosae in pigs depends on seasons The prevalence of C cellulosae depending on seasons was shown in Table 3.3 (Main thesis) Table 3.3 showed that the seasons affected the prevalence of C cellulosae in pigs in Son La and Dien Bien provinces The percentage of the larval infection, in Summer - Autumn seasons was 3.80%, in Winter - Spring was 2.15% Thus, the prevalence of C cellulosae infection in pigs in Summer - Autumn season were higher than those in Winter - Spring season because the Summer Autumn seasons are hot, humid and rainy creating favourable conditions for tapeworm eggs to exist in the external environment If people infected with T solium pass feces containing gravid proglottids into the environment, the gravid proglottids decomposed to release eggs, tapeworm eggs last for quite a long time in the outside Pigs acquire the infection after ingestion of embryonated eggs or gravid proglottids passed through human faeces 3.1.1.4 The prevalence of Cysticercus cellulosae in pigs depending on the technique of pig farming The results from infection of C cellulosae prevalence were shown in the chart in Figure 3.4 Figure 3.4 Chart of prevalence of C cellulosae infection depeding on the technique of pig farming Figure 3.4 showed that: The prevalence of C cellulosae infection was the highest in free range pigs (5.37%); followed in half free range pigs (1.94%) The lowest prevalence of infection was in pigs raised in confinement (0.66%) This rule was also found in individual pigs dissected separately in each province 12 We found that in comparison to pigs raised in confinement, free range pigs and half free range pigs have risk to expose to tapeworm eggs passing through human faeces causing higher prevalence of C Cellulosae infection 3.1.1.5 Prevalence of Cysticercus cellulosae in crossbred pigs and local pigs The results from prevalence of C Cellulosae infection were shown in Table 3.5 Table 3.5 showed that in the two provinces as a whole, the prevalence of the larval infection in local pigs was higher than that of cross bred pigs (3.84% compared to 1.98% respectively) In particular, In Son La, the prevalence of C cellulosae infection in local pigs was 3.19%, in cross bred pigs was 1.89% In Dien Bien, the prevalence of C cellulosae infection in local pigs was 4.49% in cross bred pigs was 2.08% Thus, according to the results mentioned above, the prevalence of infection between local and crossbred pigs varied However, field surveys showed that local pigs mostly were free range and halffree range while crossbred pigs were mostly raised in confinement Therefore, the larval infection in the local pig was higher than that of crossbred pigs due to technique of pig farming Therefore in order to determine whether the prevalence of larval infection depends on pig breeds, we continued to monitor the prevalence of larval infection in both the free range local pigs and crossbred pigs The results were shown in the chart in Figure 3.6 Figure 3.6 Prevalence of C cellulosae infection in the free range local pigs and crossbred pigs The chart in Figure 3.6 Showed that in the two provinces, the prevalence of larval infection in cross bred pigs and local pigs was similar when they were raised free range (5.43% compared to 5.33% respectively) Borkataki S et al (2011) reported that the prevalence of lavae infection in cross-bred pigs and local pigs was 12.53% and 7.49% respectively Our study finding was different from those of the authors mentioned.above In our opinion, when pigs are raised with the same method, the breed factor almost does not affect the prevalence of C Cellulosae infection 3.1.2 Actual situation of Taenia solium infection in humans in some districts of Son La and Dien Bien provinces 3.1.2.1 Investigation results from the current status of livestock production practices and people's living activities in some districts of Son La and Dien Bien provinces 13 Investigation results from the current status of livestock production practices and people's living activities related to prevalence of cysticercosis in pigs and T solium infection in humans were shown in Table 3.8 Table 3.8 showed: that in Son La province, households raising pigs free range acconted for 71.34% households using toilets acconted for 64.53%, but many of them whose toilets were very sparse and flimsy In Dien Bien province: households raising pigs free range accounted for 73.73% housseholds using toilets accounted 58.67% Through the investigation results we found that people's living activities and the livestock production practices were still insufficient, facilitating spreading parasitic diseases in general, and porcine cysticercosis and human Taeniasis (T solium infection) in in particular 3.1.2.2 Investigation results from the current status of people's eating habits in some districts of Son La and Dien Bien provinces Investigation results from people's eating habits related to the prevalence of C cellulosae infection in pigs and T solium infection in humans were shown in Table 3.9 Table 3.9 showed: that In Son La province people eating undercooked meat, rare meat, and smoked meat accounted for a high proportion 44.27%; 69.07% respectively In Dien Bien province, these proportions were 41.2% and 81.07% respectively From the above results, we realized that local authorities should propagate ethnic minorities not to eat rare meat or undercooked meat so that they can change their eating habits available from the ancient time; When smoked meat used, it must be cooked to decrease the prevalence of cestode infection in humans, simultaneously prevention of cestode infection in humans, which is an active measure for prevention of porcine cysticercosis; 3.1.2.3 The prevalence of tapeworm infection among investigated people in some districts of Son La and Dien Bien provinces The prevalence of T solium infection in humans among the investigated people in the two provinces was shown in Table 3.10 Table 3.10 showed that the prevalence of tapeworm infection among investigated people in districts of Son La province was 3.07% The prevalence of T solium infection among investigated people in districts of Dien Bien province was 3.86% Through the investigation, we found that Bac Yen district of Son La province and Nam Po district of Dien Bien province are remote areas of these two provinces, economic conditions, difficult transportation, and knowledge of human T solium and cysticercosis in pigs are very limited, preventive measure of the disease is not implemented, so the proportion of people infected with cestode was higher than that of the remaining districts According to the Ministry of Health (2019), the prevalence of cestode infection in humans in the midland and mountainous areas was - 6% Thus, the investigation results on the prevalence of cestode infection in humans in Son La and Dien Bien provinces were also within the rate limits announced to the public by the Ministry of Health 3.1.5 Determining the correlation between Taenia solium infection and the prevalence of Cysticercus cellulosae in pigs in Son La and Dien Bien The correlation between the prevalence of T solium infection in humans and the one of C cellulosae larval infection in pigs in Son La and Dien Bien was shown in Table 3.16 and charts in Figure 3.11a and 3.11b 14 * In Son La Province: The correlation between prevalence of T solium infection in humans and the prevalence of C cellulosae infection in pigs was positively correlated The correlation coefficient R = 0.929 proves that the correlation is very tight * In Dien Bien Province: The correlation between the prevalence of T solium infection in humans and the prevalence of C cellulosae in pigs was also positively correlated The correlation coefficient R = 0.74 indicated that the correlation was relatively tight 3.2 Study on cysticercosis in experimental infection of pigs 3.2.1 Examination of Taenia solium to cause cysticercosis in pigs * Results of comparing the similarity of nucleotide sequence of cestode samples and standard samples The CO1 gene sequences of cestode samples were with 396 bp in length The comparison results showed that the sequences were completely similar to each other, which were shown in Figure 3.12 Compared to the sequences on the Genbank (Basic Local Alinment Search Tool) by the BLAST program, these sequences had a high similarity (100%) with those of T solium species, which were shown in Table 3.17 According to BLAST results, the CO1 gene sequences of the studied samples had 100% resemblance of those of T solium species Genetic gap analysis showed that the CO1 gene sequences of the six T solium samples collected from Son La and Dien Bien (Vietnam) showed high similarity (100%) with the sequences of this species in China, Indonesia and India, which were shown in Table 3.18 On the phylogenetic tree (Figure 3.13), the CO1 gene sequence of T solium species in Vietnam was in the same branch as the CO1 gene sequence of T solium species in China, Indonesia and India Figure 3.13 A phylogenetic tree is constructed from the CO1 gene sequence using the Maximum Likekliwood method 15 3.2.2 The results of experimentally Infected cysticercosis in pigs were shown in Table 3.19 Table 3.19 showed that Pigs in experimental groups I and II, 90 - 120 days after infection, all of the larvae were fully developed at the parasitic site Number of cestode eggs infecting group I and group II was different so number of larvae at parasitic sites was also different The pigs in group II had more larvae at parasitic sites than pigs in group I with manifestation of all symptoms.mentioned previously According to Pham Van Khue and Phan Luc (1996), Pham Van Than (2009), Nguyen Thi Kim Lan (2012), the time period for C cellulosae to fully develop in pigs was 60 days Thus, our results from the larvae development time period was longer than published papers of these authors 3.2.2.1 Clinical signs in pigs with experimental cystierticosis Table 3.20 Clinical signs in pigs with experimental Cysticercosis Number percentage Of Number of pigs pigs Experimental Of manifestin manifestin group pigs g g (pig) clinical clinical signs (%) signs (pig) Expermentally Cysticercosis ìnfected group I Experimentally Cysticercosis ìnfected group II Control group 7 7 100 100 Cinical signs Major clinical signs Fever Cough Diarrhea Sore eyes and eye dischage Anorexia, slow moving Convulsion, salivasion Skinny, Pale mucosa, ruffled hair coat Erectile neck hairs trembling, grinding teeth Difficulty walking with a limp Fever Dyspnea, cough Diarrhea Sore eyes with rheum Anorexia Convulsion,salivasion Skinny, Pale mucosa, ruffled hair coat Erectile neck hairs trembling, grinding teeth Difficulty walking with a limp Number Of Percentage pigs (%) (pig) 57.14 71.43 57.14 71.43 57.14 28.57 100 100 42.85 7 100 85.71 73.43 100 85.71 57,14 100 100 71.43 0.00 16 The results in Table 3.20: showed that In experimental group I and II:1 - 10 days after infection, pigs showed clinical signs such as fever, cough, skinny, pale mucous membranes, ruffled hair coats, diarrhea, eye pain with discharge, convulsions, hypersalivasion, erected hair on the back of the neck, trembling, grinding their teeth,difficulty walking, limbing The percentage of clinical signs varied from 28.57% - 100% In the control group 7/7 pigs did not show any clinical signs In comparison between experimental infected groups: It was found that Pigs in experimental group II expressed clinical signs more severe than those in the group I 3.2.2.2 Changes in some red blood cell indices of pigs experimentally infected with C cellulosae The results were shown in fig 3.14 Figure 3.14 Chart expressing the changes in some red blood cell indices of pigs infected with C cellulosae Figure 3.14 showed that red blood cell count, Mean cell hemoglobin concentration (MCHC), Mean corpuscular volume (MCV), were all lower than those of healthy pigs in the experimental pigs; the differences in the blood parameters mentioned above between the affected pigs and control pigs was significant (P