The average direct and indirect cost of a dengue infection requiring hospital admission in Can Tho Province was US$167.77 (range = US$4.50–1,208.18). This cost was considerably more than reported for Ho Chi Minh City, which averaged US$61.36 (range = of US$5.34–280.57).6
We did not scale costs against severity but would expect that more prolonged and complicated treatments, and longer visitation periods, would result in higher cost as in this previous study. Those with insurance received a rebate between 12% and 25% depending on the services provided. Thus, it would seem that an average 22% rebate was not always sufficient to avoid hardship.
In Thailand, the total costs of one case in 1994 dollars was estimated as 37–57% of the monthly family income, at US$108.82 and US$161.49 in Bangkok and US$102.82 and US$138.02 in Suphan Buri Province for children and adults, respectively.7
In 2001 in Kamphaeng Phet Province, US$61 per case represented more than the monthly family income.8
This latter study emphasized that the cost of dengue is of the same order as other diseases given priority in Southeast Asia, namely the tropical cluster (mainly schistosomiasis, leishmaniasis, and lymphatic filariasis), malaria, meningitis, and hepatitis.
In Banteay Meanchey10
and Kampong Cham,11
Cambodia, the high socioeconomic and societal impact seemed comparable to those from Can Tho. Direct and indirect costs varied from US$8 to US$103 (2001–2002 dollars) and from US$36 to US$75 (2006–2008 dollars), respectively. Health insurance rebates were not high enough to reduce societal burden, and in Banteay Meachey at least, 63% were forced to borrow from similar sources as at Can Tho. After six months in Can Tho, more than two-thirds of those who borrowed had been unable to retire their debt; in Banteay Meanchey, this figure was 62%. Unlike the study in Cambodia,10
we did not enquire about the terms of the loan or of interest rates but it is obvious that the impact of dengue infection was highest in those who were poor.
The mean ± SD period of disability in the Can Tho cohort was 9.7 ± 4.3 days (range = 4–39 days. Before admission, 91% sought assistance mainly from private clinics and communal health centers for an average of 2.5 days. After admission to hospital for an average of 6 days, 18.1% of patients still purchased from pharmacies and private clinics but most relied on hospital treatment. This finding might indicate the level of family concern about the potential severity of dengue infection.
When we examined knowledge and risk factors, 80–96% of case and control households knew at least one dengue symptom and 95–97% knew it to be a serious or deadly disease. However approximately 6–9 months after infection, the entomologic indices for adult female Ae. aegypti in case households were similar to those where no dengue had occurred. However, numbers of late instars and pupae were lower. We cannot be certain that a case within a household did not stimulate at least some temporary activity but, overall, nominated preventive behaviors (37%) were similar for case and control households. Because our study design necessitated the questioning persons approximately 6–9 months after a dengue event to measure long-term effect, some respondents might have had recall bias. It is also possible, but unlikely, that entomologic indices in case houses may have changed relative to control houses.
Given the high impact of dengue cases, and the high level of knowledge about the habitat and behavior of Ae. aegypti
, our data suggest that few households took long-term preventive action, or more specifically any action that would effectively control the vector. However, community responsiveness is multifaceted and complex,12
and knowledge of the disease and vector may not be enough to stimulate a broad response.
Of locally promoted preventive measures, the use of covers or lids has been shown to be ineffective,13
and frequent water changing in storage jars, or upturning jars, is impractical in a poor society, which relies on water capture and storage for survival.14,15
The options of household spraying, coils, and gels would be affordable by the wealthy, and sleeping under a mosquito net is more appropriately directed against nocturnal vectors. Thus, use of fish as one practical suggestion had been adopted only by 23% of case and control households. No one had adopted Mesocyclops
use, although they were present in 3.7–6.7% of big containers, and they had been promoted as part of the National Dengue Control Plan since 1998. This prevalence is common throughout Vietnam because of water transfer practices and flooding,16,17
but their uptake as a mosquito control tool is dependent on active health promotion.
This study demonstrates that in a cohort of 144 residents of Can Tho Province in the Mekong delta region, the socioeconomic impact of one case of dengue in a household can be as high as 36% of annual income, and this can result in family hardship. Economic impact was greatest in lower income families. Our study also demonstrates that it is likely that infection may be a random event because our risk indicators suggest little difference in those households with and without dengue infection. However, both groups could have been infected at a common high-risk site, e.g., school or market.
Finally, although most households with and without dengue experience were reasonably knowledgeable about how it occurred and what to do about it, the range of options presented by health authorities was in need of reconsideration. Use of fish is well understood but although the impact of community-based Mesocyclops
has spread from northern to southern Vietnam,16,18
it requires promotion in Can Tho. On the basis of a prospective cost study during 2006–2007 in four sites in southern Vietnam,19
the cost in managing 290,000–460,000 cases in southern Vietnam was reported as averaging US$26 million per year. Based on our cohort, which might be representative of rural and provincial communities outside Ho Chi Minh City, this figure may be as high as US$48.4–76.8 million. Given the sustainability and low costs of < US$1 per person per year reported for community-based Mesocyclops
it would seem that this approach (where applicable) would be a good investment.