**2. Database search and inclusion criteria**

To ascertain the progress of the LAMP assay since it was developed by Natomi et al. [36] and further evolved by Negamine et al. [37], we conducted a database analysis by keyword search with a special focus on the genus *Giardia*. Two independent reviewers identified the records through PubMed®/MEDLINE®, the database which is considered to be the global literature, the most reliable source of literature search, and a relevant publication retrieval. Two reviewers independently extracted the data and independently assessed the methodological quality. To our best knowledge, this review aimed to assess all literature wherein the LAMP assay was developed and/or applied for detection of *Giardia* in the scientific field. The extraction of relevant literature and appraisal of the finally listed work was carried out up to March 2017. To collect precise information, the comprehensive search entailed the evaluation of published articles including full texts in the English language and those meeting the inclusion criteria were considered to be appropriate after a critical review. Our search showed one article published in the Turkish language also. We directly contacted the authors who transmitted the electronic text to us. We were able to assess the contents of the article with a translator's help. The terms "loop-mediated isothermal amplification," "loop-mediated isothermal amplification (and) *Giardia,*" "LAMP," "LAMP (and) *Giardia,*" "polymerase chain reaction," "polymerase chain reaction (and) *Giardia,*" "PCR," and "PCR (and) *Giardia*" were entered into the search box, and the articles were processed for further data extraction.

#### **2.1. Results of the literature search**

staff to their households are also possible and have a significant epidemiological impact

The Robert Koch Institute (RKI) in Berlin is the only public health institute in Germany as well as a global health hub publishing weekly reports about illnesses in the German Epidemiological Bulletin. In 2009 and 2010, about 3500–4000 cases of giardiasis were reported [29]. In 2016, the reported *Giardia* cases were 522, whereas during the first 8 weeks of 2017, the reported cases were 415 equaling to about 50 giardiasis incidences per week [30]. In industrial countries, *G. duodenalis* often occurs after the holiday seasons through returning travelers from foreign countries. The post-travel, persistent diarrheal symptoms in patients are most likely related to giardiasis, which is why it is also called "traveler's disease" [31]. Especially, backpackers transmit the parasite to their homes after

In sub-Saharan Africa (SSA), millions of people die of parasitic diseases annually. This includes neglected tropical diseases (NTDs). The geohelminths (soil-transmitted helminths [STHs]) and the intestinal *G. duodenalis* parasite alone infect hundreds of millions of people

According to the 2016 Statistical Yearbook of United Nation's High Commissioner for Refugees (UNHCR), forcibly displaced people exceeded the number of 65 million worldwide [34]. Until end of January 2016, more than 60,000 registered unaccompanied minor refugees (UMRs) were living in Germany, of which 1248 UMRs between January 2014 and December 2015 underwent an infectious disease screening. Interestingly, 29.2% (364 cases) were infected with more than one intestinal parasite and 7.6% of whom (95 cases) were diagnosed with *G.* 

To ascertain the progress of the LAMP assay since it was developed by Natomi et al. [36] and further evolved by Negamine et al. [37], we conducted a database analysis by keyword search with a special focus on the genus *Giardia*. Two independent reviewers identified the records through PubMed®/MEDLINE®, the database which is considered to be the global literature, the most reliable source of literature search, and a relevant publication retrieval. Two reviewers independently extracted the data and independently assessed the methodological quality. To our best knowledge, this review aimed to assess all literature wherein the LAMP assay was developed and/or applied for detection of *Giardia* in the scientific field. The extraction of relevant literature and appraisal of the finally listed work was carried out up to March 2017. To collect precise information, the comprehensive search entailed the evaluation of published articles including full texts in the English language and those

[26–28].

returning.

in SSA [32, 33].

*duodenalis* by immunofluorescence microscopy [35].

**2. Database search and inclusion criteria**

**1.5. Epidemiology**

112 Current Topics in Giardiasis

In total, 1850 (0.36%) of extracted articles showed for the term "loop-mediated isothermal amplification" in comparison with 512,447 for "polymerase chain reaction." The LAMP assay was first published in 2000 with a continuous increase in the following years. Until now, LAMP assays have reached the highest level in 2015 with 271 articles published, and thus far until end of March 2017, 110 articles (extrapolated ~440) have been published, which explains the increasing tendency (**Diagram 1**).

Out of 13 LAMP-related articles dealing with the detection of *Giardia,* only six articles were found related to the source/medium: water. Most of the published papers are for the purpose of method evaluation or detection of the targets in patient samples like blood, tissue, and feces. LAMP in water samples was successfully applied for *Giardia* in five articles.

**Diagram 1.** A comparative graphical representation to illustrate increase in number of publications, LAMP Vs PCR.
