Table 8.

Summary of main challenges and suggested priority research areas on FBZ in Vietnam.

Foodborne pathogen	Data on prevalence/ incidence in humans	Data on animal reservoir	Challenges for Vietnam	Suggested areas of research
Non-typhoidal Salmonella (NTS) infection	Responsible for ~0–7% of diarrhoea in <5 year children; limited data on serovar distribution in humans. High levels of NTS carriage among adults; some evidence for person-to-person transmission among children	High prevalence and variability of serovars in poultry, pigs, fish/seafood and meat products	Meeting export targets of meat products will require improved control of NTS in fish, pigs and poultry	Attribution studies in humans; impact of urbanization and backyard farming on human immunity; Antimicrobial resistance; NTS diversity within backyard versus industrialized production systems
Campylobacter spp. infection	Responsible for ~4–40% of diarrhoeal cases in <5 year children (Red River Delta)	Very high prevalence in chicken carcasses and meat products	High levels of multi-resistance including ciprofloxacin resistance	Risk factors and attribution studies among clinical cases; prevalence and genetic diversity in backyard versus industrialized production systems, and along processing/ retailing market chains; impact of urbanization and backyard farming on human immunity
Streptococcus suis infection	Most common cause of adult bacterial meningitis; majority of cases caused by S. suis serotype 2; approximately 5–43 confirmed cases per year in Vietnam	High (>40%) carriage in upper respiratory tract (tonsils) of market weight swine; predominance of S. suis 2; epidemiological interactions with viral infections (e.g. PRRSv)	Improved control over illegal marketing of ill pigs; hygiene and health quality standards in slaughter/processing facilities	Estimation of burden of disease using combined indicators for human morbidity/mortality and economic losses to swine sector; risk factors for pig colonization; development of porcine vaccines and novel diagnostic tools for herd management and risk mitigation
Listeriosis	Three clinical case reported from north Vietnam with meningitis in 2008/2009	No data	Possible increased incidence in coming years, due to greater consumption of packed food items including soft cheeses, meat and fish	Consumer perceptions of risk, health and safety in relation to highly processed foods; enhanced surveillance among high risk groups; investigation in food processing plants
Toxoplasmosis	No published data on human clinical cases. Seroprevalence in humans ranging between 1.1 and 6.4%. Higher (7.7–11%) among pregnant women and drug users in some	Very high prevalence in domestic dogs and pigs (>50%); lower in cattle and buffalo (3–10%)	Unknown risks due to poor understanding of principle zoonotic reservoir	Enhanced surveillance among pregnant women and neonates to estimate burden of disease; prevalence of oocysts in cats, dogs, dog meat and treated and untreated wastewater
Cryptosporidiosis	No published data on human clinical cases. At least two studies of paediatric diarrhoea failed to identify Cryptosporidium	High prevalence of C. parvum and C andersoni in cattle; Cryptosporidirum spp. oocysts found in pigs and farmed fish but not speciated	Risks associated with uncontrolled urbanization, peri-urban agriculture, waste water treatment and climate change	Etiological and syndromic studies of enteric disease in humans and animals; development of informal networks for reporting and investigating suspect foodborne outbreaks
Giardiasis	No published data on human clinical cases. 4% carriage of G. lamblia among healthy subjects in north Vietnam	50% of calves near Hanoi found positive by feacal microscopy; however, dominant species may be non-zoonotic G. duodenalis	Risks associated with uncontrolled urbanization, peri-urban agriculture, waste water treatment and climate change	Etiological and syndromic studies of enteric disease; species diversity in farm animals and farmed ’wild’ exotic species; risk factor studies; detection of oocysts in vegetables, treated and untreated wastewater
Taeniasis/ cysticercosis	In the late 1990s, approximately 100–150 cases/year with cerebral cysticercosis in northern Vietnam. Human surveys (2003/2004) using stool egg counts suggest low level prevalence of (0.2–7.2%). Likely to be circumscribed to certain areas in Vietnam	Multiple species identified from pigs and domestic dogs, including T. solium, T saginata asiatica	Probable future reductions in prevalence/incidence due to changes in swine production	Seroepidemiological and clinical studies. Identify host species of T. s. asiatica; studies investigating prevalence of Taenia eggs in the environment
Fascioliasis	>1,000 patients/year reported in central provinces, especially Quang Nai; seroprevalence ~8% in some areas; diagnostic case reports increasing	Hyper-endemic in ruminants of central provinces (>70% in adult cattle); high level species diversity; hybrid species identified (F. gigantica and F. hepatica)	Risks associated with changes in forage production for beef and dairy cattle	Detection of metacercariae in leaf vegetables; ecologic determinants of disease transmission; risk assessment; development of novel indicators to estimate combined disease burden in humans and animals
Leptospirosis	Highly seroprevalence in southern Vietnam suggesting endemicity. Responsible for 2–8% cases of acute jaundice. Main serovars identified Seramanga and Bataviae	Hyper-endemic in pigs in the Mekong Delta	Very common in kidneys in fattening pigs. Main serovars Bratislava, Iterohaemorrhagiae, Automnalis and Pomona	Estimate burden of infection by targeting patients with suspect hepatic and haemorrhagic syndromes. Investigate main reservoirs of infection including rats, pigs, dogs and cattle
Trichinellosis	Decreasing incidence in recent years; small outbreaks in northwest	Seroprevalence in swine ~14–20% in some areas	Probable future reductions in prevalence/incidence due to changes in swine production	Role of rodents in transmission; risks associated with specific culinary practice
Fishborne zoonotic trematode (FZT) infection	High rates of asymptomatic carriage in humans living in Red River Delta provinces (>75%)	High species diversity including both pathogenic and non-pathogenic flukes of multiple genera	Risks associated with expansion of aquaculture industry, waste water treatment and climate change	Enhanced surveillance to estimate disease burden; detection of FZT in fish; risk assessment; intervention studies; ecologic determinants of disease transmission