- Journal List
- PLoS Negl Trop Dis
- v.16(2); 2022 Feb
- PMC8853578
As a library, NLM provides access to scientific literature. Inclusion in an NLM database does not imply endorsem*nt of, or agreement with, the contents by NLM or the National Institutes of Health.
Learn more: PMC Disclaimer | PMC Copyright Notice
PLoS Negl Trop Dis. 2022 Feb; 16(2): e0010140.
Published online 2022 Feb 17. doi:10.1371/journal.pntd.0010140
PMCID: PMC8853578
PMID: 35176024
Kala Pham1,2 and Peter J Hotez
3,4,5,6,*
Aaron R. Jex, Editor
Author information Copyright and License information PMC Disclaimer
The Socialist Republic of Vietnam (Vietnam) has made tremendous strides in reducing its disease burden from tropical infections, including malaria and neglected tropical diseases (NTDs). It now joins South Korea, Japan, and the eastern half of China as nations or regions that have achieved great successes in disease control through a combination of economic reforms, mass drug preventive treatment programs, and other public health interventions [1–3]. Here, we provide a brief update on these activities, including Vietnam’s prospects for disease elimination or, in some instances, disease reemergence.
Doi Moi
Beginning in the middle 1980s, the government of Vietnam implemented a series of economic reforms under the banner of Doi Moi (“restoration”), which included market liberalizations and encouragement of private investments both domestically and from overseas. Prior to this period, Vietnam was considered among the poorest countries in Asia, but over the last 20 years, its economy has almost tripled, as its population has grown by approximately 25% to almost 100 million people [4]. More than 45 million people in Vietnam have escaped poverty over this period [4]. However, much of this economic growth has occurred disproportionately in urban areas, leaving approximately 6% of the population remaining in extreme rural poverty. Among these approximately 6 million people, 86% are considered ethnic minorities or indigenous groups [5]. Vietnam’s ethnic minorities who remain in poverty live predominantly in remote mountainous areas found in northern, western, and central regions of the country (Fig 1) [2].
The geographic regions of Vietnam.
(A) Named geographic areas. From Lee and colleagues: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0194943. (B) Topographic map showing mountainous areas. Modified from CIA Factbook: https://www.cia.gov/the-world-factbook/maps/world-regional/;https://www.cia.gov/the-world-factbook/static/35ffc797934a80da7d944dfa89624581/southeast_asia_phy.pdf.
In all, Vietnam has 54 ethnic groups, with the Kinh considered the largest [6]. While Vietnam’s ethnic minorities have protected status by the government of Vietnam, they are also recognized as socioeconomically disadvantaged, having benefited less from Doi Moi than the rest of the population [6]. They also disproportionately suffer from NTDs [7]. Compounding these vulnerabilities is Vietnam’s low level of physical capital investment compared to other Association of Southeast Asian Nations (ASEAN) nations and environmental degradation due to overfishing and deforestation [3]. Vietnam is also under threat due to climate change, with widespread flooding or even complete inundation from rising seas in its southern delta region and other low-lying coast areas [8]. Another expected consequence of climate change is warming temperatures that may promote the emergence of dengue and other vector-borne NTDs [9]. Therefore, Vietnam experiences social and physical determinants that can either promote or reduce its NTDs.
NTDs declining
Data from the Institute of Health Metrics and Evaluation find that overall, the burden of disease (in terms of disability-adjusted life years [DALYs]) from malaria and NTDs has fallen by 62% between 2000 and 2019. This includes an almost 80% decline in deaths, mostly due to malaria-related deaths [10]. Shown in Table 1 are the declines in specific NTDs, as well as malaria.
Table 1
NTDs that have declined in age-adjusted prevalence or incidence*.
| Disease | Age-adjusted prevalence cases or incidence in 2000 | Age-adjusted prevalence or incidence in 2019 | % Decline |
|---|---|---|---|
| Malaria* | 275,202.78 | 17,600.35 | 93.6 |
| LF | 2,669,033.05 | 767,798.69 | 71.23 |
| Trachoma | 40,735.88 | 18,876.41 | 53.66 |
| Soil-transmitted helminths | 44,185,437.34 | 18,477,777.10 | 58.18 |
| Rabies* | 166.83 | 93.05 | 55.77 |
*Denotes incidence data [10–14].
LF, lymphatic filariasis; NTD, neglected tropical disease.
Malaria
Prior to Doi Moi, malaria was highly endemic in Vietnam, but, together with economic reforms, a national malaria control program was established in 1992. Comprised of prompt case detection and treatment, indoor residual spraying, and the widespread distribution of insecticide-treated bednets, the incidence of new malaria cases has declined precipitously [6,15,16]. Partial support for Vietnam’s malaria program has been provided by the Global Fund to Fight AIDS, Tuberculosis and Malaria to the National Institute of Malaria, Parasitology, and Entomology (NIMPE) of the Ministry of Health (MOH) [17]. These funds have been especially helpful for supporting surveillance systems and monitoring malaria among migrants and other mobile populations [17]. However, malaria remains a significant public health threat in southern and central mountainous regions where ethnic minorities live, as well as migrants [6]. Approximately two-thirds of Vietnam’s malaria cases are caused by Plasmodium falciparum, with Plasmodium vivax making up the rest [18]. Of greatest concern is the documented emergence of artemisinin resistant malaria strains, especially in highland areas [15,16,19,20].
Lymphatic filariasis
Perhaps Vietnam’s most successful NTD control program has been its National Program to Eliminate lymphatic filariasis (LF). Launched in 2001 by the NIMPE-MOH, and with technical support from the World Health Organization (WHO) and the Global Programme to Eliminate LF [21], the national program has recently achieved elimination status [22]. The major approach includes mass drug administration with diethylcarbamazine citrate and albendazole combination therapy, or triple therapy by adding ivermectin, together with improvements linked to economic gains, including housing and water drainage infrastructure [23–25]. Since 2011, these activities accelerated through support of the United States Agency for International Development (USAID) NTD Program and its FHI360 and RTI International contractors [22]. The NIMPE-MOH is partnering with the US Centers for Disease Control and Prevention (CDC) and the Atlanta-based Task Force for Global Health to conduct operational research to help sustain and monitor LF elimination [26].
Soil-transmitted helminth infections
The 3 major soil-transmitted helminth infections—ascariasis, trichuriasis, and hookworm infection—are the most common NTDs, with more than 10% of the population of Vietnam infected. Necator americanus is a predominant hookworm species in Vietnam, but Ancylostoma ceylanicum—an often forgotten third hookworm species—is also widespread [27,28]. Vietnam’s helminth infections are concentrated in agricultural communities, particularly the Red River Delta region, due to the use of human excreta (night soil) as fertilizer and contact with contaminated water [29–31]. While the Vietnamese government has banned the use of night soil, such practice is common and low cost; therefore, it is difficult to enforce [29]. Lack of access to wastewater infrastructure, latrines that lack a chamber for long-term excreta storage, inconsistent access to commercial inorganic fertilizers, and absence of proper compost procedures all contribute to the persistence of helminth infections [29,32]. Notably, they are higher in Northern Vietnam than Southern Vietnam, either due to poverty or environmental conditions [30,33]. In response, the NIMPE-MOH provides 3 million or 5 million albendazole or mebendazole tablets annually, especially for school-age children [34,35]. However, the role of mass drug administration versus economic gains and improvements in water and sanitation and hygiene (WASH) in Vietnam’s declining prevalence is unclear. In addition, the effectiveness of drug treatments (albendazole or mebendazole) is not consistent among the 3 helminth infections [36–38]. Beyond the 3 major soil-transmitted helminth infections highlighted above, strongyloidiasis is also endemic, especially in the rural central highlands, but even in major urban areas. The highest prevalence of strongyloidiasis and evidence of clinical symptoms occurs among older rural populations [39,40].
Trachoma
Trachoma is another example of an NTD that has been effectively reduced through collaboration between USAID and the Vietnam MOH in preventive treatments with azithromycin, together with other measures. Trachoma has decreased significantly in the past years [41–43]. An ENVISION partners collaboration with the FHI 360 END project, RTI International, Fred Hollows Foundation, and the Vietnam National Institute of Ophthalmology has provided trained eye health staff and surgery procedures for trachoma from 2011 to 2016 [44]. The Fred Hollows Foundation began working in Vietnam in 1992 and since then has developed key partnerships to perform 282,000 trichiasis surgeries [45]. Additionally, WHO SAFE strategy has improved health practices significantly, which contributed to the reduction of trachoma [46]. The SAFE strategy was initiated in 1996 as part of WHO Alliance for Global Elimination of Trachoma by 2020, which worked to help countries reduce trachoma through training staff and improving health practices and programs [47,48]. The strategy has proved effective, leading to a steady decrease in trachoma prevalence; however, reinfection can occur [49]. The construction of improved sanitation and water management/facilities has also contributed to the decline of trachoma [50].
Rabies
Canine rabies is on the decline, but it remains endemic, with foci in Southern Vietnam, specifically the Mekong and Southeast Central Coast Region [51,52]. The MOH and Ministry of Agriculture and Rural Development have invested significant resources to control rabies, leading to its reduction [52]. Vietnam’s Prime Minister created the National Rabies Program in 1996, which created support and resources for rabies prevention and control. Since then, Vietnam has increased postexposure prophylaxis (PEP) centers across the country [52]. Support from WHO, World Organization for Animal Health (OIE), and the CDC have increased Vietnam’s capabilities to increase rabies awareness and improve dog surveillance, including a pilot prevention program in Thai Nguyen Province that incorporates dog registration and management [52,53].
NTDs rising
Several NTDs are increasing or reemerging. These are listed in Table 2.
Table 2
NTDs that have plateaued or increased in age-adjusted prevalence or incidence*.
| Disease | Age-adjusted prevalence cases or incidence in 2000 | Prevalence or incidence in 2019 | % Increase |
|---|---|---|---|
| Cysticercosis | 23,012.42 | 32,921.94 | 43.06 |
| Food-borne trematodiases | 637,157.76 | 940,349.37 | 47.58 |
| Cystic echinococcosis | 10.38 | 12.57 | 21.09 |
| Dengue* | 967,575.13 | 1,038,967.72 | 7.38 |
* Denotes incidence data [54–57].
NTD, neglected tropical disease.
Food-borne trematodiases
The prevalence of food-borne trematodes, especially liver fluke infection caused by Opisthorchis viverrini or Clonorchis sinensis, and intestinal fluke infections caused by Fasciolopsis buski, has increased [58,59]. Liver fluke is also an important cause of cholangiocarcioma. Opisthorchiasis is found predominantly in central southern Vietnam, whereas clonorchiasis is in northern Vietnam [60]. Vietnam’s aquaculture plays a dominant role in its economy, with freshwater fish aquaculture increasing exponentially [60]. However, the rapid rise in aquaculture is fueling the emergence of fluke infections [60,61]. For example, farmers who work on small-scale fish farms or nurseries often use livestock manure or night soil as fertilizer to help increase the growth of plankton, a food source for the fish [61].
Still, another factor is human behavior around consumption of traditional dishes containing inadequately cooked fish or fish pastes with condiments [61]. In a study conducted in Northern Vietnam, older individuals knew this risk and continued eating raw fish, because they knew drug treatment was available [62]. Many traditional dishes also utilize raw fish [58]. Furthermore, 25.8% of household members were found to have not eaten raw fish, but were infected due to cross-contamination via sharing food [62]. Finally, climate change leads to more frequent flooding, causing bodies of water with foodborne trematodes to contaminate other water supplies [62].
In summary, rising agriculture that still clings to ancient practices, including fishing practices which use feces for fertilization; increased consumption of fish because of increasing affluence by a population with a tradition of eating raw fish; and increased flooding from climate change have contributed to the rise of food-borne trematode infections.
Cysticercosis (and African swine fever)
Cysticercosis has also increased. Vietnamese citizens in peri-urban and rural areas usually have free-roaming pigs [63]. Together with open defecation using outdoor latrines, the use of night soil for agriculture maintains or accelerates this infection [47]. Similar to aquaculture, husbandry makes up a large percentage of Vietnam’s gross domestic product (GDP) and produces nearly 3,800 million tons of meat products annually [64]. Two primary types of pig and cattle husbandry practices exist: commercial farming and backyard husbandry. In rural regions, backyard husbandry practices dominate [65]. Meat inspection is only carried out at slaughter points that operate at the district level and/or clusters of large villages [63]. Vietnam’s pork production for traditional and commercial markets have a poor supply chain; therefore, the weak linkages between actors and poor hygienic practices in these chains create risk [66]. Most slaughterhouse workers seldom go through food safety training [66]. Overall improved sanitation and meat inspection/control are needed to decrease cysticercosis incidence and transmission [67]. Education and training on food safety risks and proper handling among pork value chain actors are other necessary priorities [66]. Echinococcosis is another larval cestode infection, but it is considered rare in Vietnam [68]. However, sporadic cases of hydatid disease in the heart and lung from the species Echinococcus ortleppi have been identified [68].
Dengue
Dengue epidemics now occur regularly [69]. Following a large-scale dengue fever outbreak in 2017, Vietnam recorded its highest number of dengue cases of 320,000 in 2019 [70,71]. The high population density in urban and suburban areas increases transmission and vector growth [72,73]. Climate change produces increasingly favorable precipitation, temperature, and humidity for dengue to spread [69,74]. Limited government control has curtailed improvements in dengue transmission [72]. However, because outbreaks of dengue are occurring in more frequent cycles, favorable conditions of weather, a dense human population, and rapid urbanization, there is an increased need for better governmental policy and education, including risk control, training healthcare workers to recognize dengue symptoms, and engaging local authorities [72,73]. Dengue and malaria are both mosquito borne, but the decrease in malaria can be attributed to drug treatments with artemisinin and effective centralized health programs. Both of these elements are missing with respect to dengue control. Beyond dengue, other arbovirus infections are present. For example, an Asian lineage of Zika virus infection has been detected in Vietnam and linked to microcephaly [75], and there is evidence for previous epidemics of chikungunya [76]. Japanese encephalitis is the major cause of viral encephalitis in Vietnam [77]. Transmitted by Culex mosquitoes, pigs are considered an important reservoir host [77].
Concluding statement
NTDs exhibiting the greatest declines in Vietnam appear to be those illnesses vulnerable to mass drug administration. However, given the established impact of economic improvements in also promoting reductions in the NTDs (as noted in other East Asian nations), it is difficult to confirm the contribution of mass treatments and other public health interventions. Still, another unresolved issue is whether the reductions in NTDs lead to economic improvements or vice versa. It is likely these 2 aspects are mutually reinforcing. Of interest is our finding that the impact of mass drug administration on educational attainment and development is greater in middle-income countries exhibiting lower worm burdens, compared to fragile nations with excessively high worm burdens [78]. The basis of this observation is not known, but it has been suggested that there is an accelerant effect as economies begin to improve and burdens of disease from worms diminish. This possibility is consistent with the current situation in Vietnam.
By contrast, 2 NTDs linked to agriculture and animal husbandry, liver fluke infection and cysticercosis, respectively, appear to be increasing. Paradoxically, the rises in these NTDs may reflect increases in economic development and access to expanding food sources. While this promotes food security, so far public policies to ensure these expanding agricultural practices can be conducted safely and with attention to parasite control remain lagging. This situation has also been noted in parts of China and other emerging economies of Asia. Climate change appears to accelerate these trends, as it does for dengue and vector-borne diseases. The high transmissibility of arbovirus infections will increase the reliance on the development of new vaccines.
In summary, the one-two punch of economic gains and mass drug administration is producing dramatic public health benefits in Vietnam as they have in other nations achieving middle-income status. By prioritizing NTDs, Vietnam could become a leading influencer in the Southeast Asian region. But these improvements must be accompanied by public policies around food security to control commensurate rises in food-borne trematodiases and cysticercosis and for practices to ensure the reductions in vector-borne NTDs.
Funding Statement
The authors received no specific funding for this work.
References
1. Hotez PJ, Bush K, Oswald A, Rockman G, Lim IT, Jee Y, et al. A new Korean research investment for global health technology (RIGHT) fund to advance innovative neglected-disease technologies. PLoS Negl Trop Dis. 2020:1–5. doi: 10.1371/journal.pntd.0007956 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
2. Dung DT, van De N, Waikagul J, Dalsgaard A, Chai J-Y, Sohn W-M, et al. Fishborne zoonotic intestinal trematodes, Vietnam. Emerg Infect Dis. 2007;13: 1828+. Available from: https://link-gale-com.ezproxy.lib.uh.edu/apps/doc/A172746395/SCIC?u=txshracd2588&sid=bookmark-SCIC&xid=631371e5. doi: 10.3201/eid1312.070554 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
3. Mapping Vietnam’s Poverty Indicators. [cited 2021 Oct 6]. Available from: https://blogs.worldbank.org/eastasiapacific/mapping-vietnam-poverty-indicators.
4. Overview: Development news, research, data | World Bank. [cited 2021 Oct 6]. Available from: https://www.worldbank.org/en/country/vietnam/overview#1.
5. Bank W, Vietnam M of P and I of. Vietnam 2035.Vietnam 2035: Toward Prosperity, Creativity, Equity, and Democracy. 2016. [cited 2021 Oct 6]. doi: 10.1596/978-1-4648-0824-1 [CrossRef] [Google Scholar]
6. Målqvist M, Hoa DTP, Liem NT, Thorson A, Thomsen S. Ethnic minority health in Vietnam: a review exposing horizontal inequity.Glob Health Action. 2013;6:1–19. doi: 10.3402/gha.v6i0.19803 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
7. Schratz A, Pineda MF, Reforma LG, Fox NM, le Anh T, Tommaso Cavalli-Sforza L, et al. Chapter 4—Neglected Diseases and Ethnic Minorities in the Western Pacific Region: Exploring the Links. In: Zhou X-N, Bergquist R, Olveda R, Utzinger J, editors. Advances in Parasitology.Academic Press; 2010. pp. 79–107. doi: 10.1016/S0065-308X(10)72004-2 [PubMed] [CrossRef] [Google Scholar]
8. VIETNAM CLIMATE RISK COUNTRY PROFILE. 2020 [cited 2021 Oct 6]. Available from: www.worldbank.org.
9. Messina JP, Brady OJ, Golding N, Kraemer MUG, Wint GRW, Ray SE, et al. The current and future global distribution and population at risk of dengue.Nat Microbiol. 2019/06/10. 2019;4: 1508–15. doi: 10.1038/s41564-019-0476-8 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
10. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/b56319a954ab8b3297078cb743803b86.
11. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/f8cda237e2d9b70506b1110c08c85eac.
12. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/44d95234ff1baea3c0e7e0cd92b1d2bf.
13. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/5958543aac81a29f75188c34ffd853d1.
14. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/f447175412ec1c8ff3de045775e5f504.
15. Malaria in Viet Nam. [cited 2021 Oct 6]. Available from: https://www.who.int/vietnam/health-topics/malaria.
16. Goldlust SM, Thuan PD, Giang DDH, Thang ND, Thwaites GE, Farrar J, et al. The decline of malaria in Vietnam, 1991–2014.Malar J. 2018;17:226. doi: 10.1186/s12936-018-2372-8 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
17. New Global Fund Grant Aims for Malaria Elimination in the Mekong—News & Stories—The Global Fund to Fight AIDS, Tuberculosis and Malaria. [cited 2021 Oct 6]. Available from: https://www.theglobalfund.org/en/news/2017-04-25-new-global-fund-grant-aims-for-malaria-elimination-in-the-mekong/.
18. van Long B, Allen G, Brauny M, Linh LTK, Pallerla SR, Huyen TTT, et al. Molecular surveillance and temporal monitoring of malaria parasites in focal Vietnamese provinces. Malar J. 2020;19:458. doi: 10.1186/s12936-020-03561-6 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
19. Peak CM, Thuan PD, Britton A, Nguyen TD, Wolbers M, Thanh NV, et al. Measuring the Association Between Artemisinin-Based Case Management and Malaria Incidence in Southern Vietnam, 1991–2010. Am J Trop Med Hyg. 2015;92:811–7. doi: 10.4269/ajtmh.14-0461 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
20. Viet Nam ready to eliminate malaria. [cited 2021 Oct 6]. Available from: https://www.who.int/vietnam/news/detail/23-04-2018-viet-nam-ready-to-eliminate-malaria.
21. A bright future: Eliminating lymphatic filariasis in Vietnam | by RTI | Int’l Dev | Medium. [cited 2021 Oct 6]. Available from: https://rti-intl-dev.medium.com/a-bright-future-eliminating-lymphatic-filariasis-in-vietnam-776bae245c8c.
22. Vietnam Eliminates Lymphatic Filariasis as a Public Health Problem—Neglected Tropical Disease Program. [cited 2021 Oct 6]. Available from: https://www.neglecteddiseases.gov/vietnam-eliminates-lymphatic-filariasis-as-a-public-health-problem/.
23. Meyrowitsch DW, Toan ND, Hao HT, Dan NT, Michael E. A review of the present status of lymphatic filariasis in Vietnam. Acta Trop. 1998;70: 335–47. doi: 10.1016/s0001-706x(98)00037-0 [PubMed] [CrossRef] [Google Scholar]
24. Dung DT, Binh VTL, Worrell CM, Brady M, Walsh V, Yajima A, et al. Evaluation of a facility-based inspection tool to assess lymphedema management services in Vietnam.PLoS Negl Trop Dis. 2020;14:1–13. doi: 10.1371/journal.pntd.0008773 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
25. Macfarlane CL, Budhathoki SS, Johnson S, Richardson M, Garner P. Albendazole alone or in combination with microfilaricidal drugs for lymphatic filariasis. Cochrane Database Syst Rev.2019;1:CD003753–CD003753. doi: 10.1002/14651858.CD003753.pub4 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
26. Vietnam eliminates lymphatic filariasis, a disfiguring disease | RTI. [cited 2021 Oct 6]. Available from: https://www.rti.org/news/vietnam-eliminates-lymphatic-filariasis-disfiguring-disease.
27. Bui K-L, Nguyen T-H, Duong HD, Nguyen V-L, Nguyen T-N, Le L-A, et al. Ancylostoma ceylanicum infections in humans in Vietnam. Parasitol Int. 2021;84:102405. doi: 10.1016/j.parint.2021.102405 [PubMed] [CrossRef] [Google Scholar]
28. Hung BK, van De N, van Duyet L, Chai J-Y. Prevalence of Soil-Transmitted Helminths and Molecular Clarification of Hookworm Species in Ethnic Ede Primary Schoolchildren in Dak Lak Province, Southern Vietnam.Korean J Parasitol. 2016/08/31. 2016;54:471–76. doi: 10.3347/kjp.2016.54.4.471 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
29. Tran-Thi N, Lowe RJ, Schurer JM, Vu-Van T, MacDonald LE, Pham-Duc P. Turning poop into profit: Cost-effectiveness and soil transmitted helminth infection risk associated with human excreta reuse in Vietnam.PLoS Negl Trop Dis. 2017;11:e0006088–8. doi: 10.1371/journal.pntd.0006088 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
30. Pham-Duc P, Nguyen-Viet H, Hattendorf J, Zinsstag J, Phung-Dac C, Zurbrügg C, et al. Ascaris lumbricoides and Trichuris trichiura infections associated with wastewater and human excreta use in agriculture in Vietnam. Parasitol Int. 2013;62: 172–80. doi: 10.1016/j.parint.2012.12.007 [PubMed] [CrossRef] [Google Scholar]
31. Uga S, Hoa NT, Thuan le K, Noda S, Fujimaki Y. Intestinal parasitic infections in schoolchildren in a suburban area of Hanoi, Vietnam.Southeast Asian J Trop Med Public Health. 2005.
32. Fuhrimann S, Winkler MS, Pham-Duc P, Do-Trung D, Schindler C, Utzinger J, et al. Intestinal parasite infections and associated risk factors in communities exposed to wastewater in urban and peri-urban transition zones in Hanoi, Vietnam.Parasit Vectors. 2016;9:537. doi: 10.1186/s13071-016-1809-6 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
33. van der Hoek W, van De N, Konradsen F, Cam PD, Hoa NTT, Toan ND, et al. Current status of soil-transmitted helminths in Vietnam. Southeast Asian J Trop Med Public Health. 2003;34Suppl 1: 1–11. [PubMed] [Google Scholar]
34. Dang-Xuan S, Nguyen-Viet H, Meeyam T, Fries R, Nguyen-Thanh H, Pham-Duc P, et al. Food Safety Perceptions and Practices among Smallholder Pork Value Chain Actors in Hung Yen Province, Vietnam. J Food Prot. 2016;79: 1490–97. doi: 10.4315/0362-028X.JFP-15-402 [PubMed] [CrossRef] [Google Scholar]
35. Millions of Vietnamese women to be dewormed | Health | Vietnam+ (VietnamPlus). [cited 2021 Oct 6]. Available from: https://en.vietnamplus.vn/millions-of-vietnamese-women-to-be-dewormed/80748.vnp.
36. Else KJ, Keiser J, Holland CV, Grencis RK, Sattelle DB, Fujiwara RT, et al. Whipworm and roundworm infections. Nat Rev Dis Primers. 2020;6:44. doi: 10.1038/s41572-020-0171-3 [PubMed] [CrossRef] [Google Scholar]
37. Patel C, Coulibaly JT, Schulz JD, N’Gbesso Y, Hattendorf J, Keiser J. Efficacy and safety of ascending dosages of albendazole against Trichuris trichiura in preschool-aged children, school-aged children and adults: A multi-cohort randomized controlled trial. EClinicalMedicine. 2020;22. doi: 10.1016/j.eclinm.2020.100335 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
38. Moser W, Schindler C, Keiser J. Efficacy of recommended drugs against soil transmitted helminths: systematic review and network meta-analysis. BMJ. 2017;358:j4307. doi: 10.1136/bmj.j4307 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
39. Diep NTN, Thai PQ, Trang NNM, Jäger J, Fox A, Horby P, et al. Strongyloides stercoralis seroprevalence in Vietnam. Epidemiol Infect. 2017;145:3214–8. doi: 10.1017/S0950268817002333 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
40. van De N, Minh PN, van Duyet L, Mas-Coma S. Strongyloidiasis in northern Vietnam: epidemiology, clinical characteristics and molecular diagnosis of the causal agent. Parasit Vectors. 2019;12:515. doi: 10.1186/s13071-019-3776-1 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
41. Nguyen DH. Prevention and treatment of trachoma and the anti-blindness program.Rev Int Trach Pathol Ocul Trop Subtrop Sante Publique. 1991;68:171–7. English. French. [PubMed] [Google Scholar]
42. Nguyên DT. Aperçu sur le problème du trachome au Viêt-Nam [Perception of the problem of trachoma in Vietnam].Rev Int Trach Pathol Ocul Trop Subtrop Sante Publique. 1990;67:193–201. French. [PubMed] [Google Scholar]
43. Trachoma. [cited 2021 Oct 6]. Available from: https://www.who.int/westernpacific/health-topics/trachoma.
44. ENVISION Project | IMA World Health. [cited 2021 Oct 6]. Available from: https://imaworldhealth.org/envision.
45. Vietnam | Fred Hollows Foundation. [cited 2021 Oct 6]. Available from: https://www.hollows.org/us/where-we-work/south-east-asia/vietnam-2.
46. Tian L, Wang N-L. Trachoma control: the SAFE strategy.Int J Ophthalmol. 2018;11:1887–8. doi: 10.18240/ijo.2018.12.01 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
47. Hiep NX, Ngondi JM, Anh VT, Dat TM, van An T, Dung NC, et al. Trachoma in Viet Nam: results of 11 surveillance surveys conducted with the Global Trachoma Mapping Project. Ophthalmic Epidemiol2018;25: 93–102. doi: 10.1080/09286586.2018.1477964 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
48. WHO Alliance for the Global Elimination of Trachoma by 2020 (GET 2020). [cited 2021 Oct 6]. Available from: https://www.who.int/initiatives/who-alliance-for-the-global-elimination-of-trachoma-by-2020.
49. Atik B, Thanh TTK, Luong VQ, Lagree S, Dean D. Impact of Annual Targeted Treatment on Infectious Trachoma and Susceptibility to Reinfection. JAMA. 2006;296:1488–97. doi: 10.1001/jama.296.12.1488 [PubMed] [CrossRef] [Google Scholar]
50. Khandekar R, Thanah TTK, do Thi P, Impact of Face Washing and Environmental Improvement on Reduction of Active Trachoma in Vietnam—A Public Health Intervention Study. Ophthalmic Epidemiol.2006;13:43–52. doi: 10.1080/09286580500477507 [PubMed] [CrossRef] [Google Scholar]
51. Lee HS, Thiem VD, Anh DD, Duong TN, Lee M, Grace D, et al. Geographical and temporal patterns of rabies post exposure prophylaxis (PEP) incidence in humans in the Mekong River Delta and Southeast Central Coast regions in Vietnam from 2005 to 2015.PLoS ONE. 2018;13:e0194943–3. doi: 10.1371/journal.pone.0194943 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
52. Nguyen HTT, Afriyie DO, Tran CH, Dang AD, Tran DN, Dang TQ, et al. Progress towards rabies control and elimination in Vietnam. Rev Sci Tech. 2019.
53. USAID Strengthens One Health Collaboration in Vietnam to Fight Infectious Disease Threats | Program Update | Vietnam | U.S. Agency for International Development. [cited 2021 Oct 6]. Available from: https://www.usaid.gov/vietnam/program-updates/aug-2018-usaid-strengthens-one-health-collaboration-vietnam-fight-infectious-disease.
54. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/fd46ba614b8ec7a04130410912af8a65.
55. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/0d29c20925ca5816abb52ac27b24f263.
56. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params=gbd-api-2019-permalink/f6ac0d4096a556607383c3cffa70d48b.
57. GBD Results Tool | GHDx. [cited 2021 Oct 7]. Available from: http://ghdx.healthdata.org/gbd-results-tool?params.
58. Nguyen PTX, van Hoang H, Dinh HTK, Dorny P, Losson B, Bui DT, et al. Insights on foodborne zoonotic trematodes in freshwater snails in North and Central Vietnam. Parasitol Res. 2021;120:949–62. doi: 10.1007/s00436-020-07027-1 [PubMed] [CrossRef] [Google Scholar]
59. Sripa B, Suwannatrai AT, Sayasone S, Do DT, Khieu V, Yang Y. Current status of human liver fluke infections in the Greater Mekong Subregion. Acta Trop. 2021;224:106133. doi: 10.1016/j.actatropica.2021.106133 [PubMed] [CrossRef] [Google Scholar]
60. Keiser J, Utzinger J. Emerging Foodborne Trematodiasis. Emerg Infect Dis. 2005;11:1507. doi: 10.3201/eid1110.050614 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
61. Phan VT, Ersboll AK, Nguyen TT, Nguyen KV, Nguyen HT, Murrell D, et al. Freshwater aquaculture nurseries and infection of fish with zoonotic trematodes, Vietnam. Emerg Infect Dis. 2010;16:1905+. Available from: https://link-gale-com.ezproxy.lib.uh.edu/apps/doc/A246535175/SCIC?u=txshracd2588&sid=bookmark-SCIC&xid=8d175fe9. doi: 10.3201/eid1612.100422 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
62. Clausen JH, Madsen H, Murrell KD, Van PT, Thu HNT, Do DT, et al. Prevention and control of fish-borne zoonotic trematodes in fish nurseries, Vietnam. Emerg Infect Dis. 2012;18:1438+. Available from: https://link-gale-com.ezproxy.lib.uh.edu/apps/doc/A303450766/HRCA?u=txshracd2588&sid=bookmark-HRCA&xid=40c029f1. doi: 10.3201/eid1809.111076 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
63. Ng-Nguyen D, Stevenson MA, Traub RJ. A systematic review of taeniasis, cysticercosis and trichinellosis in Vietnam.Parasit Vectors. 2017;10:150. doi: 10.1186/s13071-017-2085-9 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
64. Ng-Nguyen D, Traub RJ, Nguyen V-AT, Breen K, Stevenson MA. Spatial distribution of Taenia solium exposure in humans and pigs in the Central Highlands of Vietnam. PLoS Negl Trop Dis. 2018;12: e0006810–. Available from: doi: 10.1371/journal.pntd.0006810 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
65. van De N, Le TH, Lien PTH, Eom KS. Current status of taeniasis and cysticercosis in Vietnam. Korean J Parasitol. 2014/04/18. 2014;52:125–29. doi: 10.3347/kjp.2014.52.2.125 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
66. Nguyen Thi Thuy M, Dorny P, Lebailly P, le Thi MC, Nguyen Thi Thu H, Dermauw V. Mapping the pork value chain in Vietnam: a systematic review. Tropl Anim Health Prod. 2020;52:2799–808. doi: 10.1007/s11250-020-02338-y [PubMed] [CrossRef] [Google Scholar]
67. Willingham AL 3rd, De NV, Doanh NQ, Cong le D, Dung TV, Dorny P, et al. Current status of cysticercosis in Vietnam.Southeast Asian J Trop Med Public Health. 2003;34(Suppl 1):35–50. . [PubMed] [Google Scholar]
68. De N van Minh PN, van Duyet L Bich NN, Son TN Jung B-K, et al. Two Human Cases of Echinococcus ortleppi Infection in the Lung and Heart in Vietnam.Korean J Parasitol. 2020/08/25. 2020;58:451–456. doi: 10.3347/kjp.2020.58.4.451 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
69. Vo TQ, Phuong Pham TT. Revisiting dengue-related knowledge, attitudes and practices: A cross-sectional study in Ho Chi Minh City, Vietnam, 2018. J Pak Med Assoc. 2019.
70. Nguyen LH, Tran BX, Do CD, Hoang CL, Nguyen TP, Dang TT, et al. Feasibility and willingness to pay for dengue vaccine in the threat of dengue fever outbreaks in Vietnam.Patient Prefer Adherence. 2018;12:1917–26. doi: 10.2147/PPA.S178444 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
71. Dengue and severe dengue. [cited 2021 Oct 6]. Available from: https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue.
72. Nguyen-Tien T, Do DC, Le XL, Dinh TH, Lindeborg M, Nguyen-Viet H, et al. Risk factors of dengue fever in an urban area in Vietnam: a case-control study. BMC Public Health. 2021;21:664. doi: 10.1186/s12889-021-10687-y [PMC free article] [PubMed] [CrossRef] [Google Scholar]
73. Dengue increase likely during rainy season, Ministry of Health, WHO warn. [cited 2021 Oct 6]. Available from: https://www.who.int/vietnam/news/detail/16-07-2019-dengue-increase-likely-during-rainy-season-ministry-of-health-who-warn.
74. Xuan LTT, van Hau P, Thu DT, Toan DTT. Estimates of meteorological variability in association with dengue cases in a coastal city in northern Vietnam: an ecological study. Glob Health Action. 2014;7:23119. doi: 10.3402/gha.v7.23119 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
75. Grant R, Nguyen TTT, Dao MH, Pham HTT, Piorkowski G, Pham TDT, et al. Maternal and neonatal outcomes related to Zika virus in pregnant women in Southern Vietnam: An epidemiological and virological prospective analysis. Lancet Reg Health West Pac. 2021;11:100163. doi: 10.1016/j.lanwpc.2021.100163 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
76. Quan TM, Phuong HT, Vy NHT, le Thanh NT, Lien NTN, Hong TTK, et al. Evidence of previous but not current transmission of chikungunya virus in southern and central Vietnam: Results from a systematic review and a seroprevalence study in four locations. PLoS Negl Trop Dis. 2018;12: e0006246–e0006246. doi: 10.1371/journal.pntd.0006246 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
77. Ha T v, Kim W, Nguyen-Tien T, Lindahl J, Nguyen-Viet H, Thi NQ, et al. Spatial distribution of Culex mosquito abundance and associated risk factors in Hanoi, Vietnam.PLoS Negl Trop Dis. 2021;15:e0009497–. Available from: doi: 10.1371/journal.pntd.0009497 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
78. Kang S, Damania A, Majid MF, Hotez PJ. Extending the global worm index and its links to human development and child education. PLoS Negl Trop Dis. 2018;12:e0006322–. Available from: doi: 10.1371/journal.pntd.0006322 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
Articles from PLOS Neglected Tropical Diseases are provided here courtesy of PLOS
