| ObjectiveCryptosporidium is a kind of enteric protozoan parasite that has emerged as an important cause of diarrhea among humans and animals. Human cryptospo-ridiosis is almost attributed to Cryptosporidium parvum. Since the first report of the disease in 1987 covered by Hanfan et al, in Nanjing, many reports of the disease have been published from more than ten provinces in our country. The epidemiological information about the disease has not been reported up to date in Iiaoning province. Due to serious lack of a precise etiology examination and deficiency of experience for the disease, cryptosporidiosis is usually misdiagnosed, which may delay timely treatment. Therefore, an accurate convenient effective diagnostic method is of important significance for diagnosing and therapying the disease. In this study, we carry out the following study considering clinical application : (1) To investigate cryptosporidiosis prevalence of different population including patients suffering from diarrhea and drug users in Shenyang, to compare the Cryptosporidial infection rate among different sex groups and age groups and occupation groups, to provide scientific evidence for prevention and controlling of cryptosporidiosis; (2) To contrast effectivity and practicability among iodine stain and chlorazol black stain and modified acid fast(MAFS) stain, to develop a associated stain method containing 2 steps for examinating oocysts of Cryptosporidium, to provide methodological evidence for diagnosis and epidemiological survey; (3 ) To attempt to establish mouse model for Cryptosporidium by Dexamethasone administered in drinking water, to provide insights for propagating cryptosporidium and studying pathogenic mechanism and developing new target agents.Methods1. The inducement of mouse to infect Cryptosporidium10 KM neonatal 10 day mice were required, ordinarily fed and induced im-munosuppression orally by DEX treated in drinking water. If the fecal staining result was consistent with that provided by Pro. Zhang from the Quartermarster University of PLA, the result that Cryptosporidial oocysts occurred in feces should be affirmed. Then, mouse feces were collected for positive reference. Dead mice were necropsied and intestines were observed.2. The collection of human fecal specimens283 fecal specimens were collected from out - patients suffering from diarrhea and 70 specimens from drug users. Every portion is approximately 1.5 ~2. 0ml volume, a majority of samples were detected in time, the samples that had not been examinated were mixed with 5.0% potassium dichromate of equal volume, stored at 4℃ and examinated next day.3. Etiological examinationEvery fecal sample was routine smeared and examined by iodine staining method for oocysts, the positive or suspected positive samples were identified by chlorazol black and modified acid fast(MAFS) staining method. The examination under microscope was taken respectively. The samples in which Cryptosporidial oocysts was insufficient were used the method of the Saccharu solution floating concentrate for oocysts.4. Statistic analysisTo determine the statistic obvious difference by x2 test, the result had the meaning if P <0. 05.Result1. The inducing result of mouse infected by Cryptosporidium The onset of oocyst shedding occured on induced day 5, maximum of oocysts was seen on day 6, afterword amount of oocysts was in decreasing day byday. Symptoms such as depression and reducing appetite occurred on day 9. 7 mice died on day 12 and 3 died on day 13. Stool obtained from intestines was examinated by microscope under oil X 1,000, Cryptosporidial oocysts was full of visual field.2. The stain characteristics of cryptosporidiumWhen stained by an iodine staining, oocysts were round and uncolored, fecal debris and yeasts was colored brown yellow; When stained using an modified acid fast method, oocysts of cryptosporidium stained bright red, background was blue green. As seen in the preparation, 4 crescent sporozoites and black granular relicts were visible inside the oocysts; When by means of chlorazol black staining method, oocysts and background were also black, the oocyst wall was clearer than that by modified acid fast staining, other characteristics including the size of oocyst and sporozoites were consistent with those by modified acid fast staining.3. The infection rate of human cryptosporidiumOut of 353 samples, 28 positive and suspected specimens were found by iodine staining, 15 specimens were both positive by the latter two method, others were negative, the positive rate was 4. 25% ; A case infected by fungus was i-dentified by chlorazol black staining method, the infection rate was 3. 18% a-mong the patients with diarrhea, the positive rate was 8. 57% among the drug users, there was significant difference in the infection rates of the two groups; there was no significant difference in the infection rates between the male and the female with diarrhea; in children and the adults aged older than 18 years, the positive rates were7. 31% and 1. 19% respectively, there was significant difference in the positive rates.4. Clinical manifestation9 cases of Cryptosporidial infection from patients suffering from diarrhea was shown, whose general symptom contained watery stool, abdominal pain, nausea, vomiting, fever, anorexia and lose of body weight. The first diagnose included acute enteritis , chronical enteritis and dyspepsia. 1 positive case was AIDS patient who had been in AIDS for 2 years and in diarrhea intermittently for 2 months, symptom of diarrhea began to aggravate 10 days before diagnose. 6... |
PDF Full Text Request