Seroprevalence and genetic characterization of Toxoplasma gondii in cancer patients in Anhui Province, Eastern China

Abstract

BackgroundRecent studies have indicated the predominance of Toxoplasma gondii genotype Chinese 1 in animals in China. However, little is known of the genetic features of the parasite in humans. This study aims to determine the prevalence of anti-T. gondii antibodies based on which the genetic character of the parasite was identified in cancer patients in China.MethodsA total of 1014 serum samples with malignant neoplasms were collected from six tertiary-care hospitals (HAUCM, APH, HAMU, XAH, FHH and HBMC) from January, 2012 to August, 2013. Antibodies against T. gondii were examined by enzyme-linked immunosorbent assay (ELISA). Blood samples were subsequently used for PCR assay to detect T. gondii DNA (gra6). The DNA positive samples were subjected to genotyping using a multiplex multilocus nested PCR-RFLP at 10 loci, including sag1, sag2, sag3, btub, gra6, l358, c22-8, c29-2, pk1 and apico. Samples from the patients were anonymous and only data with regard to age and gender was available at sample collection.ResultsOverall, 8.38% (85/1014) of the examined patients showed positive antibodies against T. gondii. Among them, 61 (6.02%) were seropositive only for IgG, 16 (1.58%) were only for IgM, and 8 (0.79%) were found to be positive for both IgG and IgM. The seroprevalence of antibodies to Toxoplasma ranged from 5.8% to 11.0%, without regional difference (χ2 = 4.764, P = 0.445). No significant differences of the positive rates of T. gondii infection were noted in genders (male, 8.96%; female, 7.45%) (χ2 = 0.707, P = 0.400) and in ages (χ2 = 1.172, P = 0.947). Of 1014 DNA samples, 36 (3.55%) were positive for T. gondii by nested PCR at gra6 locus and nine gave rise to complete genotyping results. All samples with achieved PCR-RFLP genotyping showed a common genetic character of type Chinese 1 (ToxoDB#9).ConclusionSeroprevalence of toxoplasmosis in immunosuppressed individuals is rarely reported in China and we presented a positive rate of 8.38% in cancer patients. Toxoplasma genomic DNA genotyping demonstrated a common genetic character of Chinese 1, indicating a possible pathogenic origin of animals in human infection.

The relationship between toxoplasmosis and different types of human tumors

“…These results suggested higher prevalence than that of Wang et al who reported 8.96% prevalence of antibodies to T. gondii in male cancer patients and 7.45% in females. These findings could be due to the geographical variation and genetic susceptibility [15]. As the functions of the immune system are disturbed in patients with aneoplasm [16], toxoplasmosis has been described in association with some malignancies [13].…”

Seroprevalence and risk factors of Toxoplasma gondii infection in oral cancer patients in China: a case–control prospective study

“…Nearly one-third of the world's population is thought to be infected with this parasite [2]. The prevalence rate of T. gondii in China is over 7% and this rate is constantly rising due to the rapid growth of the number of cats (pet and stray cats) [3][4][5]. This parasite has three infective forms: the tachyzoite, the bradyzoite inside tissue cysts and the sporozoite in sporulated oocyst [6].…”

“…Cancer patients who are seronegative for T. gondii infection could benefit from advice on precautionary measures, to avoid seroconversion that may induce active severe toxoplasmosis [15]. Therefore, potential associations between T. gondii infection and cancer have attracted a lot of attention [3,4,[16][17][18][19][20][21][22][23][24][25][26]. Oral cancer is one of the most common malignant tumours.…”

Prevalence of Toxoplasmosis Among Cancer Patients.

“…Also it showed the presence of severe infection in some samples with toxoplasmosis and cancer patients. The presence of acute infection in previous studies mentioned above due to the nature of the studied groups some of them were members of the workers in the massacres, and the other were pregnant women while the rest were couples as well as other samples were randomly taken, especially pregnant women and those were workers in the massacres which is exposed to risk factors from workers who could be infected with acute toxoplasmosis in the current study, the presence of severe infection consistent with both Nimir and others (2015), [7] and Wang et al;, [8] who pointed to the existence of severe infection toxoplasmosis among patients of cancer and in spite of the presence of acute infection. Those patients did not show 1365 symptoms of toxoplasmosis.…”

“…Those patients did not show 1365 symptoms of toxoplasmosis. The severe infection among these patients due to the low level and the efficiency of the immune system have as a result of cancer and receiving chemotherapy, making them susceptible to many diseases, including toxoplasmosis, especially in the event of exposure to risk factors such as during water contaminated food and eating or contact with cats or dealing with contaminated materials infectious those phases of the parasite (meat, dust and other) (Mahammad and others, 2012; Wang et al, 2015) [8,9]. Khudair (2012) [10] and Kalantari ,N. et al; [11] .…”