Epidemiological survey of cryptosporidiosis in Anhui Province China

AIM:To provide scientific evidence for prevention andcontrolling of cryptosporidiosis,the infection ofCryptosporidium parvum and its epidemiologicalcharacteristics were studied in some areas of Anhui Province.METHODS:The oocyst of Cryptosporidium parvum in 5421fresh stool samples from eleven areas of Anhui Provincewas tested by auramine-phenol stain and improved anti-acidstain respectively.The specific antibody of IgG,IgM and Tsubsets of 41 patients with positive Cryptosporidium parvumin stools were detected by ELISA and biotin-streptavidin(BSA)respectively.RESULTS:The total infective rate of Cryptosporidiumparvum was 1.33%(74/5421).Among them,the positiverates of oocyst in the areas of Huaibei(1.82%)and Fuyang(1.80%)were higher.The positive rates of oocyst in stoolsof infants,pupils,middle school students,collegestudents,adults,patients with diarrhea,and those withimmunodeficiency were 3.15%(28/889),0.82%(9/1098),0.82%(9/1092),0.83%(8/969),0.85%(9/1095),2.88%(8/278)and 8.33%(3/36)% respectively.The positive rates ofoocyst in infants and the patients with diarrhea andimmunodeflciency were significantly higher than those incontrols(P<0.01).The positive rate of oocyst in maleswas similar to that in females(P>0.05).The positive rateof oecyst in urban areas(1.13%)was significantly lowerthan those in rural areas(1.72%,P<0.01).The positiverates of specific IgG,IgM and IgG+IgM in sera of thepatients with positive oocyst in stool were 63.4%(26/41),17.1%(7/41),19.5%(8/41)respectively.The numberfractions of T subsets of CD3~+,CD4~+,CD8~+ and CD4~+/CD8~+ of the patients were 0.66±0.07,0.44±0.06,0.28±0.04 and 1.58±0.32 respectively.The difference between thepatients and the controls was significant(P<0.05).Themain manifestations of the patients were subclinicalinfection,in forms of slight abdominal pain,mild diarrhea,and loose stool.CONCLUSION: There are two infection peaks in infection of Cryptosporidium parvum and its infection can be found more often in infants, patients with diarrhea or immunodeficiency, and in rural areas. Subclinical infection is the main manifestation and might be easily misdiagnosed. When the therapeutic effectiveness is low for diarrhea, the infection of Cryptosporidium parvum should be considered, concerning their age and immune function.