Application of molecular genotyping to determine prevalence of HPV strains in Pap smears of Kazakhstan women

Prevalence of high-risk human papillomavirus infection and genotype distribution among Kazakhstani women with abnormal cervical cytology

AIM

This study aimed to identify the prevalence and distribution of high-risk human papillomavirus (HR-HPV) types among Kazakhstani women with abnormal cervical cytology.

METHODS

A cross-sectional study was performed from May 2019 to June 2020. Cervical samples were collected from women in the different regions of Kazakhstan.

RESULTS

A total of 316 patients' samples were analysed for HR-HPV using real-time multiplex PCR. Cervical cytology abnormalities were reported according to the Bethesda classification. HPV detection by cytology showed a statistically significant association with HPV status and the number of HPV infection types (p < .05). Among women with abnormal cervical cytology, 62.4% were positive for HPV infection of those 79.4% had low-grade squamous intraepithelial lesions (LSIL), and 20.6% had high-grade squamous intraepithelial lesions (HSIL). Among patients with LSIL, 77.4% had HPV16 and 58.8% were infected with HPV18. Among patients with HSIL, 41.2% had HPV18 and 22.6% - HPV16.

CONCLUSIONS

There is a high prevalence of HR-HPV types among Kazakhstani women with abnormal cervical cytology. The most identified types were HPV16, 18, 31, 33 and 52. There is an emergency need to implement an HPV vaccination program to prevent cervical lesion development.

Prevalence of Precancerous Cervical Lesions among Nonvaccinated Kazakhstani Women: The National Tertiary Care Hospital Screening Data (2018)

OBJECTIVE

At the present time, cervical cancer remains the fourth most prevalent cancer among women worldwide. Most cervical cancer cases are attributed to high-risk human papillomavirus (HPV) infection. Because the natural history of cervical cancer takes decades, the disease could be prevented if premalignant conditions are identified and appropriately managed. The aim of this study is to identify the prevalence of precancerous lesions among non-vaccinated women attending the national tertiary care hospital in Kazakhstan.

METHODS

This was a retrospective study of the cervical cancer screening database (2018) from the national tertiary care hospital in Kazakhstan. Records of 6682 patients, who had cervical cytology tests by Papanicolaou (Pap test), were analyzed. Out of the revised cases, 249 patients had abnormal cervical cytology reports. The Pap test was performed using liquid-based cytology (LBC). The data were analyzed using the statistical software STATA 16. A p-value of less than 0.05 was considered statistically significant.

RESULTS

In this retrospective analysis of 6682 patients' records, we found 3.73% (249 patients) out of all Pap tests performed in 2018 were abnormal. The prevalence of high-grade squamous intraepithelial lesion (HSIL) was high at 19.28%, and the proportion of atypical squamous cells of undetermined significance (ASCUS) and atypical squamous cells (ASCs-H) was 18.47%, while low-grade squamous intraepithelial lesion (LSIL) were identified in 62.25% of the cases. Almost 25% of the women included in the study had concurrent lower and upper genital tract infections.

CONCLUSION

Although the overall rate of abnormal Pap test results was not high, the study shows the elevated prevalence of HSIL. It calls the attention of local policymakers and gynecology specialists and requires immediate actions to improve the prophylactic measures to decrease morbidity and mortality from cervical cancer in Kazakhstan.

Knowledge and attitudes of mothers toward HPV vaccination: A cross-sectional study in Kazakhstan

BACKGROUND

Although recommended for all member states of World Health Organization, there is no national human papillomavirus vaccination program in Kazakhstan. Furthermore, there are no studies in Kazakhstan that evaluate the mothers' perception of human papillomavirus vaccines.

OBJECTIVES

This study aims to assess the knowledge and attitudes toward human papillomavirus vaccination among mothers in Kazakhstan and the factors associated with their attitudes.

DESIGN

A cross-sectional study was performed during the period of December 2021-February 2022. The STROBE guideline for cross-sectional studies was applied.

METHODS

Paper-based structured questionnaires were filled out by 191 mothers, 141 of whom had daughters. The attitude score was assessed as per the Likert-type scale. The Chi-square and Fisher's exact tests, with a significance value of < 0.05 were used to analyze the relationships between the characteristics of mothers and their attitude scores.

RESULTS

The following factors were significantly associated with mothers' attitudes toward human papillomavirus vaccination: a place of residence, family income, number of children, and refusal of vaccination for themselves (p < 0.005). Of all participants, only 45% of all mothers, 41% of mothers with a female, and 46% of mothers with male children had positive attitudes toward human papillomavirus vaccination. The child's gender was not a significant determinant. Overall, the level of knowledge about human papillomavirus vaccination was found to be low. The median total score is 0 out of 12 for women who have negative and neutral attitudes toward human papillomavirus vaccines. Among women who have positive attitudes toward HPV vaccines, the median score is around 3 points.

CONCLUSION

Before the implementation of the human papillomavirus vaccination program into the Kazakhstani national vaccination calendar, comprehensive and adequate information and education campaigns are required on the national level for parents and the population in general.

A unique Levey-Jennings control chart used for internal quality control in human papillomavirus detection

OBJECTIVE

The purpose of this study was to provide an updated estimate of the prevalences of different types of human papillomavirus (HPV) in females in Chaoshan District and to establish an internal quality control (IQC) method for excluding false-positive results in HPV detection by using the Levey-Jennings control chart.

METHOD

HPV types were detected in 23,762 cervical samples by using PCR membrane hybridization. The means and standard deviations (SDs) of the positive rates were calculated, the Levey-Jennings chart was plotted, and the rules for "out of control" and "warning" were established. A set of standardized IQC for HPV DNA tests was developed based on the values and Levey-Jennings charts.

RESULT

In 466 batches, the positive rate exceeded the 1 + 2SD rule 24 times, but there was no consecutive exceedance, which was considered "in control". When the positive rate exceeded the 1 + 3SD rule 8 times with consecutive exceedance, it was considered "out of control". Further examination revealed that detections showing "out of control" had an undesirable random error, indicating that contamination may occur due to improper operation.

CONCLUSION

This unique Levey-Jennings control chart is a practical method for eliminating false-positive results in HPV DNA detection and should be widely applicable in molecular diagnostic laboratories.

What Factors Are Associated with Attitudes towards HPV Vaccination among Kazakhstani Women? Exploratory Analysis of Cross-Sectional Survey Data

Background. The high prevalence of HPV infection among Kazakhstani women and the absence of an HPV vaccination program are directly reflected in increasing rates of cervical cancer incidence and mortality. Kazakhstan made its first attempt at introducing the HPV vaccine in 2013, but was unsuccessful due to complications and low public acceptance. The attitudes of Kazakhstani women towards the vaccine were never measured. Therefore, this study aims to investigate the attitudes of women towards the HPV vaccine and determine factors associated with positive, negative, or neutral attitudes. Methods. A 29-item survey consisting of 21 demographic and contextual questions and 8 Likert-scale questions was distributed among women attending gynecological offices in four major cities of Kazakhstan from December 2021 until February 2022. Attitudes of women were measured based on their answers to the eight Likert-scale questions. Ordinal logistic regression was built to find associations between demographic characteristics and attitudes of women. Results. Two hundred thirty-three women were included in the final analysis. A total of 54% of women had positive attitudes towards the vaccine. The majority of women did not trust or had a neutral attitude towards the government, pharmaceutical industry, and traditional and alternative media. However, the trust of women was high in medical workers and scientific researchers. Women's age, education, number of children, effect of the 2013 HPV program, and trust in alternative medicine were included in the ordinal logistic model. Women with a low level of education, a high number of children, who believe in alternative medicine, and who were affected by the failed 2013 vaccination program were less likely to have a positive attitude towards the vaccine. Conclusions. Contrary attitudes towards HPV vaccination exist among Kazakhstani women, with approximately half having positive and almost half having negative or neutral attitudes towards the vaccine. An informational campaign that takes into consideration women's levels of trust in different agencies, as well as targets those who are the most uninformed, might help in a successful relaunch of the HPV vaccination program. However, more studies that cover a higher number of women are required.

Knowledge and awareness of human papillomavirus infection and human papillomavirus vaccine among Kazakhstani women attending gynecological clinics

Cervical cancer remains one of the top causes of cancer-related morbidity and mortality all over the world. Currently, however, there are no published studies to assess the knowledge of HPV and cervical cancer in Kazakhstan. This study aimed to assess the awareness of HPV, the knowledge of HPV as a cause of cervical cancer, and the awareness of HPV vaccination among Kazakhstani women visiting gynecological clinics across the country. In addition, the study aimed to identify the factors associated with the awareness of HPV and the HPV vaccine and knowledge of HPV as a major cause of cervical cancer. This was a cross-sectional survey-based study with 2,272 women aged between 18–70 years attending gynecological clinics, who were administered paper-based questionnaires. Data analysis included descriptive statistics consisting of mean values, standard deviations, and frequencies, where applicable. Differences in categorical variables between groups were analyzed using the Chi-square test with a significance value of <0.005. Crude odds ratio (OR) and adjusted odds ratio (AOR) with 95% corresponding confidence intervals were calculated in regression analysis using univariate and multivariable logistic regression models. The mean age of participants was 36.33±10.09 years. More than half (53%) of the participants had been screened for cervical cancer. Among those who were aware of HPV, 46% knew that HPV causes cervical cancer and 52% were aware of the HPV vaccine. The key factors related to outcome variables were age, ethnicity, education, family, number of deliveries, and menarche. From a subgroup analysis, results from the HPV test and Pap smear test were factors related to dependent variables such as awareness of HPV and awareness of HPV vaccination.

The Distribution and Prevalence of High-Risk HPV Genotypes Other than HPV-16 and HPV-18 among Women Attending Gynecologists' Offices in Kazakhstan

Simple Summary

This study focused on the prevalence of high-risk human papilloma virus (HR-HPV) infection types, other than HPV-16 and -18, in women throughout Kazakhstan due to the high rates of cervical cancer in Kazakhstani women. Approximately one quarter of the of the participants were infected with HR-HPV types other than HPV-16 and -18; 72% of these women were infected with one HR-HPV type with HPV-31 being the most prevalent, and the remaining 28% of these infected women were infected with multiple HR-HPVs with HPV-68 being the most prevalent type in these women. Introducing HR-HPV testing for all 14 cancerogenic types into cervical cancer screening program could help to reduce the rates of cervical cancer in Kazakhstan.

Abstract

Cervical cancer represents a great burden to public health of women. This study aimed to obtain a nationwide genotyping survey and analysis of high risk-HPV including those that are caused by HPV types other than HPV-16 and HPV-18, among women in Kazakhstan. This study was conducted based on the collection of survey and cervical swabs of 1645 women across the country. The samples were genotyped for high-risk HPV types based on real-time PCR methods. Collected data was analyzed with the focus on high-risk HPV types other than HPV-16 and -18. Infection was present in 22% of women who participated in the study. The most prevalent types were HPV-31 among single infections and HPV-68 among multiple infections. Conclusively, despite the lack of attention high-risk HPV types beyond HPV-16 and -18 get in attempts of cervical cancer prevention in Kazakhstan, their prevalence is high and plays a large role in cervical cancer epidemiological situation.

Prevalence and genotype distribution of human papillomavirus infection in Huzhou City, eastern China, 2018-2019

BACKGROUND

Human papillomavirus (HPV) infection is involved in cervical cancer development, and hence understanding its prevalence and genotype distribution is important. However, there are few reports on the prevalence and genotype distribution of HPV in the city of Huzhou in China.

METHODS

In this retrospective cross-sectional study, 11,506 women who visited Huzhou Maternity & Child Health Care Hospital between January 2018 and October 2019 were enrolled. The results of HPV genotyping and cytology tests were analyzed.

RESULTS

The overall prevalence of HPV infection was 15.5%. The rate of high-risk (HR) HPV infection (13.5%) was higher than that of single low-risk (LR) HPV infection (2.0%) (p<0.05). The five most common HPV genotypes were HPV52 (3.3%), 16 (1.9%), 58 (1.7%), 53 (1.5%), and 81 (1.2%). The infection rate of HPV peaked in women aged 16-24 and women aged ≥55. The infection rate of HPV58 or HPV81 appeared as a single peak in women aged ≥55. The rates of HR-HPV and LR-HPV infection were higher in subjects with abnormal cytology (p<0.05).

CONCLUSIONS

HPV infection is high in Huzhou, and HPV53 and HPV81 are the prevalent genotypes. HPV infection rate is associated with age and cytology. Regional HPV surveillance is essential to optimize current HPV prevention and vaccine development.

Prevalence of high-risk human papillomavirus infection among Kazakhstani women attending gynecological outpatient clinics

OBJECTIVES

To conduct a nationwide high-risk human papillomavirus (HR-HPV) infection genotyping analysis of women attending gynecological clinics and identify factors associated with HR-HPV infection.

METHODS

A cross-sectional survey-based study with 759 participants. Demographics, lifestyle, and medical history data were collected by questionnaire completed by gynecologists during patients' visits. Cervical swabs were used for HPV genotyping using AmpliSens kit. Data analysis included descriptive statistics consisting of mean values, standard deviations, and frequencies, where applicable. Ordinal logistic regression was performed to identify factors associated with HPV infection status.

RESULTS

The mean age of participants was 36.51 ± 10.09 years. The majority of participants were aged 26-35 years. Less than half of the women (39%) were HPV positive; 26% had single HR-HPV, and 13% had multiple HR-HPV infection. The most prevalent HR-HPV genotypes were HPV-16 (54%), HPV-51 (7%), HPV-68 (7%), and HPV-18 (6%). Ordinal logistic regression demonstrated that older age, not being single, and having a history of sexually transmitted infections, decrease the odds of HPV infection.

CONCLUSION

This study identified high prevalence of HR-HPV among Kazakhstani women. Our results showed that adding HPV testing to compulsory cervical cancer screening in Kazakhstan could improve the screening program and decrease cervical cancer rates.

Human Papillomavirus Selected Properties and Related Cervical Cancer Prevention Issues

High-risk human papillomavirus strains are widely known to be the causative agents responsible for cervical cancer development. Aggregated damage caused by papillomaviruses solely is estimated in at least 5% of all malignancies of the human body and 16% in cancers that affect the female genital area. Enhanced understanding of the complex issue on how the high extent of carcinogenicity is eventually formed due to the infection by the Papoviridae family would contribute to enhancing current prevention strategies not only towards cervical cancer, but also other HPV associated cancers. This review article is aimed at presenting the key points in two directions: the current cervical cancer prevention and related aspects of HPV behavior. Virtually all applied technologies related to HPV diagnostics and screening programs, such as HPV tests, colposcopy-based tests (VIA/VILI), conventional and liquid-based cytology, currently available are presented. Issues of availability, advantages, and drawbacks of the screening programs, as well as vaccination strategies, are also reviewed in the article based on the analyzed sources. The current point of view regarding HPV is discussed with emphasis on the most problematic aspect of the HPV family concerning the observed increasing number of highly carcinogenic types. Present trends in HPV infection diagnostics throughout the human fluids and tissues are also reported, including the latest novelties in this field, such as HPV assay/self-sample device combinations. Besides, a brief outline of the related prevention issues in Kazakhstan, the leading country of Central Asia, is presented. Kazakhstan, as one of the post-soviet middle-income countries, may serve as an example of the current situation in those terrains, concerning the implementation of globally accepted cervical cancer prevention strategies. Along with positive achievements, such as the development of a nationwide screening program, a range of drawbacks is also analyzed and discussed.

Human Papillomavirus Infection and Cervical Cancer: Epidemiology, Screening, and Vaccination-Review of Current Perspectives

Viral infections contribute as a cause of 15–20% of all human cancers. Infection by oncogenic viruses can promote different stages of carcinogenesis. Among many types of HPV, around 15 are linked to cancer. In spite of effective screening methods, cervical cancer continues to be a major public health problem. There are wide differences in cervical cancer incidence and mortality by geographic region. In addition, the age-specific HPV prevalence varies widely across different populations and showed two peaks of HPV positivity in younger and older women. There have been many studies worldwide on the epidemiology of HPV infection and oncogenic properties due to different HPV genotypes. However, there are still many countries where the population-based prevalence has not yet been identified. Moreover, cervical cancer screening strategies are different between countries. Organized cervical screening programs are potentially more effective than opportunistic screening programs. Nevertheless, screening programs have consistently been associated with a reduction in cervical cancer incidence and mortality. Developed countries have achieved such reduced incidence and mortality from cervical cancer over the past 40 years. This is largely due to the implementation of organized cytological screening and vaccination programs. HPV vaccines are very effective at preventing infection and diseases related to the vaccine-specific genotypes in women with no evidence of past or current HPV infection. In spite of the successful implementation of the HPV vaccination program in many countries all over the world, problems related to HPV prevention and treatment of the related diseases will continue to persist in developing and underdeveloped countries.

HPV genotype prevalence and distribution during 2009-2018 in Xinjiang, China: baseline surveys prior to mass HPV vaccination

Background

The aim of this paper was to conduct a baseline survey of HPV infection in unvaccinated women in Xinjiang Uyghur Autonomous Region before the mass use of HPV vaccine.

Methods

Between 2008 and 2018, the HPV genotype detected by a PCR-based hybridization gene chip assay of 37,722 women who were from Gynecology Department and Health Management Center of the First Affiliated Hospital of Xinjiang Medical University were tested HPV genotype by a PCR-based hybridization gene chip assay. All statistical analysis methods were performed with this statistical software including Python version 3.6.1, R Software 3.5.1 and Excel 2011.

Results

The total positive rate for HPV was 14.02%, the most prevalent genotypes were HPV 16 (3.79%), HPV 52 (2.47%), HPV 58 (1.76%), HPV 53 (1.35%) and HPV 31 (0.72%). The single infection (11.34%) and high-risk HPV (HR-HPV) infection (9.72%) was the main prevalence of HPV. Age-specific HPV distribution was presented as a bimodal curve, while the youngest age group (≤25 years) presented the highest HPV infection rate (20.78%), which was followed by a second peak for the 36–40 age group. According to the ethnic stratification, the HPV infection prevalence ranging from the high to low was: Mongol (16.36%), Hui (15.15%), Kazak (14.47%), Han (14.43%), Other (14.37%), Uygher (10.96%). From 2009 to 2013, the HPV infection rate fluctuated but did not changed much. It peaked in 2014 and then fell significantly, reached the bottom point in 2017 and rose slightly in 2018. In 2015, the infection rate of HPVl6 and 52 in the population was almost the same (both 3.40%) the infection rate of HPV52 type (3.31%) was higher than that of HPVl6 type (2.18%) and became the dominant type in 2016.

Conclusions

We present data regarding the prevalence and type distribution of HPV infection, which could serve as the valuable reference to guide nationwide cervical cancer screening. These baseline data enable the estimates of maximum HPV vaccine impact across time and provide critical reference measurements which are important to the assess of clinical benefits and potential harms in HPV vaccination and the increase in non-vaccine HPV types.

HPV Types Distribution in General Female Population and in Women Diagnosed with Cervical Cancer Across Western Kazakhstan

Objective:

to detect the HPV types distribution both in general female population and in women with first diagnosed cervical cancer, including viral load in both groups.

Methods:

Qualitative detection and quantification of HPV was performed by PCR-Real time method based on the Russian equipment and test systems (“DNA-Technology” LLC, Russia). The DNA of low-risk (HPV 6, 11, 44) and possibly / potentially / high carcinogenic risk (HPV 16, 18, 26, 31, 33 , 35, 39, 45, 51, 52, 53, 56, 58, 59, 66, 68, 73, 82), a total of 21 types, were detected.

Results:

During the period of 2014-2017 total 1,166 clinically healthy women were tested for HPV, as well as 73 women diagnosed with CaCx. Overall prevalence of HPV in female population was determined as 25.0% (95% CI 22.3;27.7, p = 0.05). Top-5 leading HPV types: 16 (26.4%); 31 (10.1%); 51 (9.4%); 52 (9.0%); 6 (7.9%). Average viral load was 5.5±3.8 (CI 95% 5.1;5.9). In women diagnosed with CaCx ranking was as follows – 16 (54.1%), 31 (11.2%), 18 / 58 (5.1% each), 33 / 45 (4.1% each). Type 16 appeared to be one of the most significant risk factors of the CaCx development (p=0.00007, phi 0.35, Pierson’s X ² 15.9). Average viral load in patients with CaCx was 6.9±4.0 (95% CI 6.1;7.7). A reliable relationship between the cancer staging and the viral load was found (p = 0.043, n = 73). Domination of type 16 calls for urgent need the transition to HPV primary screening and resumption of immunization program discontinued in 2014. The study is registered in ISRCTN registry, No. ISRCTN71514910 (01.02.2018).

Epidemiology of HPV Infection and HPV-Related Cancers in Kazakhstan: a Review

Background: Cancer is one of the most prevalent causes of mortality worldwide. In the cervix it is considered to be caused by different high-risk human papillomavirus (HPV) types. Although many studies have already been conducted worldwide on the epidemiology of HPV infection and their oncogenic properties, limited data are available on HPV prevalence, incidence and genotype specific dissemination in Kazakhstan. Methods: To review the distribution of HPV infection, electronic databases (e.g. PubMed, Web of Science and Google Scholar) were searched for peer reviewed articles in English. The study was performed during June-July 2017 with a review of 39 relevant articles, published up to July 31, 2017. The following inclusion criteria were applied: general population data, cytology results available, and use of polymerase chain reaction (PCR) and/or Hybrid Capture® 2, Digene Corp., USA for HPV detection. Results: As reported in limited studies, the prevalence of HPV infection in Kazakhstan ranges from 43.8% to 55.8%. However, the scenario with regard to epidemiology of HPV related cancers in Kazakhstan is not very clear. One study reported a decline of laryngeal cancer observed during the recent years, whereas cervical cancer incidence has increased to about 3000 new cervical cancer cases, and about 1,000 cervical cancer deaths each year. Conclusion: The high incidence of cervical cancer with a significant mortality rate in Kazakhstan is evidence of HPV infection abundance despite an absence of HPV screening and low public awareness of the problem. Having a well-informed understanding of the role of HPV infection could enhance the public’s acceptance of screening and intervention programs to reduce morbidity and mortality in the country due to HPV infection. Thus, the purpose of this review article is to summarize the existing data, identifying directions for future research on HPV epidemiology and HPV-related diseases in Kazakhstan.

HPV infection and P16 expression in oral and oropharyngeal cancer in Kazakhstan

Background

Human papillomavirus (HPV) is an important etiologic factor in different cancers of anogenital region and also in a fraction of head and neck cancers (HNC) particularly oropharyngeal tumors. The HPV16 genotype associated with the majority of HPV-related head and neck carcinomas. Th incidence of oropharyngeal cancer is increasing in many countries, and the rate of HPV positive tumors is about 70% in Europe and North America. Little known about the prevalence of HPV in HNC in Central Asia.

Methods

It’s a prospective analysis of patients with verified oral or oropharyngeal cancer. Sociodemographic and clinical data obtained on admission to treatment. The diagnosis of HPV positivity assessed by both the P16 expression on immunohistochemistry(IHC) and polymerase chain reaction (PCR)with HPV DNA detection and HR HPV type determination.

Results

Seventy six patients with oral and oropharyngeal cancer tested for HPV. Forteen cases were positive for HPV by PCR and 15 cases by P16 IHC. Of the 35 oropharyngeal tumors, nine were HPV DNA and p16 IHC positive, giving the rate of 25.7%. Of the 41 oral tumors, five were HPV DNA and six p16 IHC positive, giving the rate of 12.2%.

Conclusion

It is the first study mapping prevalence of HPV positivity in oral and oropharyngeal cancer in the Central Asian region. The rate of HPV positivity was higher in oropharyngeal than in oral cancer, the nonsmokers were significantly more frequent in the HPV positive group and HPV 16 was the most frequent type. However, the HPV positivity rates are lower than referred in the western world.

Prevalence and genotype distribution of human papillomavirus among females in the suburb of Shanghai, China

To describe the prevalence of human papillomavirus (HPV) and its genotype distribution among females in the suburb of Shanghai. A total of 33 562 participants were enrolled in this study from January to December 2016. HPV GenoArray test kit was used to perform HPV genotyping and was also used in DNA amplification and HybriBio's proprietary flow-through hybridization technique. The overall prevalence of HPV was 18.98% and the top ten genotypes of HPV infection were HPV 16 (3.36%), HPV 58 (2.65%), HPV 52 (2.48%), HPV 51 (1.58%), HPV 54 (1.40%), HPV 68 (1.32%), HPV 18 (1.23%), HPV 6 (1.15%), HPV 56 (1.10%), and HPV 33 (1.07%). Single infection (4749, 14.15%) was the most common types among all the infected cases. Significant differences were found among age groups and month groups in terms of simple and multiple infection (P < 0.05), pure HR, LR and mixed HPV infection (P < 0.05). The prevalence of HR and LR HPV infection among females in the suburb of Shanghai is high, prevalence of single and multiple infection, pure HR, LR and mixed infection is correlated with the age and month.