**4. Conclusions**

As mentioned above, PURE and LAMP system have been newly developed and successfully applied as a novel diagnostic platform for the detection of infectious diseases, which are wildly endemic in the developing world. This platform has the advantage of being simple enough to be applicable in resource-limited facilities and its performances is higher than those of the existing diagnostic methods routinely employed in rural laboratories of most of the developing countries. Recently, a novel idea for performing LAMP without electricity has been proposed (LaBarre et al., 2011). Combination of that technology with the platform mentioned in this chapter would make it possible to realize the use of molecular diagnostics in poorer settings or even in field conditions.

Since the geographical distribution of malaria, HAT, and TB overlap in many of tropical countries (Cook & Zumla, 2003), diagnostic tests for these diseases are often performed at the same rural laboratory in developing countries. The developed platform described in this study is a very useful tool in such laboratories because all the above mentioned diseases can be diagnosed using almost the same technique and the same simple incubator. This new technology can be beneficial as it reduces the initial costs associated with installing new equipments and preparing trained technicians for each target. This platform is potentially applicable to other pathogens, including those causing other neglected diseases such as leishmaniasis and Chagas' disease. The application of this platform could be extended to other diseases that threaten the heath and quality of life of patients in many tropical countries. This can also contribute to distribute them at more affordable rates because of the effect of mass production.

This platform can be considered as a gene point-of-care testing (g-POCT) device, which can also be used in developed countries. In fact, TB-LAMP has been approved as clinical in vitro diagnostics (IVD) in Japan and used along with PURE as a simple and fast screening test for patients suspected with TB. Since NALC-NaOH treatment for sputum is not necessary for PURE-TB-LAMP, turn-around-time of PURE-TB-LAMP is less than that of the decontaminated smear test, which is commonly adopted as the standard screening test for TB in most developed countries. Furthermore, LAMP reagents using similar concepts have been developed for the detection of the influenza virus (Nakauchi, 2011). We hope that the platform will contribute to the improvement of global health and benefit all those under the threat of infectious diseases.

### **5. Acknowledgments**

We sincerely thank Dr. Satoshi Mitarai from the Research Institute of Tuberculosis in Japan, Dr. Noboru Inoue from Obihiro University of Agriculture and Veterinary Medicine in Japan, Dr. C.J. Sutherland and Dr. S.D. Polley from the London School of Hygiene and Tropical Medicine in the UK, and Dr. N.T. Lan from the Pham Ngoc Thach Hospital in Vietnam for their valuable help. This research was supported by the Foundation for Innovative New Diagnostics (FIND) in Switzerland.

#### **6. References**

454 Current Topics in Tropical Medicine

the PURE-TB-LAMP assay can detect the pathogen with 60% accuracy in smear-negative but culture-positive samples, and with 75% or more accuracy if 20 colonies are detected by the culture test using Ogawa media. This data clearly shows that the PURE-TB-LAMP method is reliable enough to be applied to the targeted peripheral smear centers in developing

As mentioned above, PURE and LAMP system have been newly developed and successfully applied as a novel diagnostic platform for the detection of infectious diseases, which are wildly endemic in the developing world. This platform has the advantage of being simple enough to be applicable in resource-limited facilities and its performances is higher than those of the existing diagnostic methods routinely employed in rural laboratories of most of the developing countries. Recently, a novel idea for performing LAMP without electricity has been proposed (LaBarre et al., 2011). Combination of that technology with the platform mentioned in this chapter would make it possible to realize the use of molecular diagnostics

Since the geographical distribution of malaria, HAT, and TB overlap in many of tropical countries (Cook & Zumla, 2003), diagnostic tests for these diseases are often performed at the same rural laboratory in developing countries. The developed platform described in this study is a very useful tool in such laboratories because all the above mentioned diseases can be diagnosed using almost the same technique and the same simple incubator. This new technology can be beneficial as it reduces the initial costs associated with installing new equipments and preparing trained technicians for each target. This platform is potentially applicable to other pathogens, including those causing other neglected diseases such as leishmaniasis and Chagas' disease. The application of this platform could be extended to other diseases that threaten the heath and quality of life of patients in many tropical countries. This can also contribute to distribute them at more affordable rates because of the

This platform can be considered as a gene point-of-care testing (g-POCT) device, which can also be used in developed countries. In fact, TB-LAMP has been approved as clinical in vitro diagnostics (IVD) in Japan and used along with PURE as a simple and fast screening test for patients suspected with TB. Since NALC-NaOH treatment for sputum is not necessary for PURE-TB-LAMP, turn-around-time of PURE-TB-LAMP is less than that of the decontaminated smear test, which is commonly adopted as the standard screening test for TB in most developed countries. Furthermore, LAMP reagents using similar concepts have been developed for the detection of the influenza virus (Nakauchi, 2011). We hope that the platform will contribute to the improvement of global health and benefit all those under the

We sincerely thank Dr. Satoshi Mitarai from the Research Institute of Tuberculosis in Japan, Dr. Noboru Inoue from Obihiro University of Agriculture and Veterinary Medicine in Japan, Dr. C.J. Sutherland and Dr. S.D. Polley from the London School of Hygiene and Tropical Medicine in the UK, and Dr. N.T. Lan from the Pham Ngoc Thach Hospital in Vietnam for their valuable help. This research was supported by the Foundation for Innovative New

countries as an alternative method for the direct smear test.

in poorer settings or even in field conditions.

**4. Conclusions** 

effect of mass production.

threat of infectious diseases.

Diagnostics (FIND) in Switzerland.

**5. Acknowledgments** 


**26** 

*USA* 

**Sexually Transmitted Infections in the Tropics** 

*University of Mississippi Medical Center, Department of Microbiology, Jackson, MS* 

The burden of sexually transmitted infections (STIs) on the health and well-being of the population in the developing world is considerable. The World Health Organization (WHO) estimates that there are 340 million new cases of curable STIs in the world each year; 174 million new cases of trichomoniasis, 92 million new cases of *Chlamydia* infection, 62 million cases of gonorrhea, and 12 million new cases of syphilis (Table 1). Approximately three quarters of these infections are in countries encompassing tropical regions of the world in Latin America, sub-Saharan Africa, and South and Southeast Asia. The prevalence of viral STIs is even higher; infection with Herpes simplex virus-2 (HSV-2) is the most common STI worldwide and as many as 50% of sexually active individuals will be infected with human papillomavirus (HPV) during their life. The prevalence of STIs is considerably greater than many classical tropical diseases and it is unfortunate that they do not receive more attention and resources from international programs and donor groups. The public health impact of these diseases extends well beyond the immediate effects and morbidities of infection. STIs have been implicated in facilitating acquisition and transmission of HIV, in pregnancy complications such as pre-term births, low birth weight infants, stillbirth, neonatal death and blindness, in the inducement of cervical and prostate cancers, and in increased risk of pelvic inflammatory disease and infertility. Failure to diagnose and treat STIs at an early stage thus increases the already substantial burden these conditions impose on the populations of developing countries. Although effective diagnostic tests and treatments are available for these STIs, they are often unavailable or inaccessible in resource-limited tropical settings. As a consequence, syndromic management of STIs remains the option of choice for individual case management. The inadequate public health response coupled to ongoing socioeconomic and demographic trends have led to an epidemic of STIs in many countries in the developing world. The development of antimicrobial resistance is an ongoing problem and new agents are often much more expensive, increasing the burden of control. The economic costs of these diseases and their infection sequelae place a considerable burden on national health budgets and household income. In developing countries, STIs are among the top five reasons for which adults seek medical care. Due to the prevalence and public health implications of STIs in the tropics a discussion of STIs should

This chapter will cover sexually transmitted infections caused by *Trichomonas vaginalis* (trichomoniasis), *Chlamydia trachomatis* (chlamydia and lymphogranuloma venereum), *Neisseria gonorrhoeae* (gonorrhea), *Treponema pallidum* (syphilis), *Haemophilus ducreyi*

**1. Introduction** 

be included in any compilation of tropical medicine.

John C. Meade and Denise C. Cornelius

