Comparison of the diagnostic performance of microscopic examination, Copro-ELISA, and Copro-PCR in the diagnosis of Capillaria philippinensis infections

Abstract

Intestinal capillariasis is a parasitic zoonosis caused by the tiny nematode parasite Capillaria philippinensis. It is a major health problem that may lead to death if not diagnosed and treated appropriately. The difficulties in the diagnosis of C. philippinensis highlight the importance of developing accurate, sensitive, and specific methods for early diagnosis. This study aimed to detect the presence of C. philippinensis infection among 42 clinically suspected patients with certain criteria that are highly suggestive of capillariasis and to compare the diagnostic yield of microscopy, copro-ELISA, and PCR for the detection of copro-DNA. Sociodemographic characteristics and clinical data were also described for the infected group. Out of 42 patients, 10 were microscopically positive, 40 samples were positive by copro-ELISA, nested PCR detected 35 positive cases, with total detection rates of 23.8%, 95.2%, and 83.3% using direct microscopic examination, copro-ELISA, and PCR, respectively. The majority of positive cases were females, middle-aged people, and people from rural areas. The real number of cases infected with C. philippinensis may far exceed those estimated using microscopy. The diagnosis by copro-ELISA for the detection of C. philippinensis coproantigen and by nested PCR to identify parasite DNA revealed a higher number of positive cases. Using ELISA for the detection of coproantigen is a sensitive test that identifies the infection, yet it is not specific. Copro-DNA offers a satisfactory sensitive and specific method for the detection of infection in clinically suspected patients. The most susceptible individuals to C. philippinensis infection are females, middle-aged people, and people of low social standards. Intestinal capillariasis needs to be considered in patients who present with symptoms of chronic diarrhea and hypoalbuminemia because if these cases are left undiagnosed and untreated, they may suffer from lethal complications.

Evaluation of Semi-Nested PCR Compared with Indirect-ELISA to Diagnose Human Fasciolosis

“…ELISA (use of ESPs) and molecular (DNA-based) methods for diagnosis of clonorchiasis were used, like fascioliasis ( 26 ). Besides, copro-ELISA and copro-PCR were able to detect intestinal capillariasis in 95% and 83% of fecal samples, respectively ( 27 ). In another study, 100% similarity of nested PCR ( B1 T. gondii gene) and ELISA (IgG Ab) results (63% of samples by two methods) was observed in the diagnosis of chronic toxoplasmosis ( 28 ).…”

Comparison of polymerase chain reaction and microscopy for the detection of Fasciola spp. in the fecal matter of domestic bovines in Kalasin Province, Thailand

“…The remaining sediment was mixed by autopipetting, and one drop was added to a drop of saline on a glass slide. The sediment was covered with a coverslip and examined microscopically using 10× and 40× objectives for the presence of Fasciola egg forms [ 21 ].…”

“…Therefore, eggs in the stool cannot be found before the PPP has been completed [ 18 - 20 ]. Molecular diagnosis by PCR can reduce the limitations of microscopic diagnosis of fasciolosis [ 21 ]. In addition, PCR can report the results of the current infection [ 16 ].…”

High Prevalence of Intestinal Capillariasis in Chronic Diarrhea Patients in Thailand: Serological Screening Using a Rapid Lateral-Flow Immunochromatographic Assay

“…6,7 Recently, detection of copro-DNA of C. philippinensis using nested PCR has been suggested as a sensitive and specific diagnostic tool in clinically suspected patients. 8 Current immunological methods can also support diagnosis of intestinal capillariasis. These include coproantigen detection by a capture ELISA, 8,9 antibody detection by immunoblotting, 10,11 ELISA, 12 and a point-of-care (POC) immunochromatography test (ICT) using patient serum.…”

“…8 Current immunological methods can also support diagnosis of intestinal capillariasis. These include coproantigen detection by a capture ELISA, 8,9 antibody detection by immunoblotting, 10,11 ELISA, 12 and a point-of-care (POC) immunochromatography test (ICT) using patient serum. 13 The last three antibodydetection methods exhibit high diagnostic values.…”