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Year : 2022  |  Volume : 21  |  Issue : 1  |  Page : 39-42  

Dengue seropositivity among blood donors in a tertiary hospital in Kerala, Southern India

1 Department of Microbiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
2 Department of Transfusion Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India

Date of Submission15-Jul-2020
Date of Acceptance29-Jul-2021
Date of Web Publication18-Mar-2022

Correspondence Address:
Nandita Shashindran
Department of Microbiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi - 682 041, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/aam.aam_72_20

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Aim: The aim of this study was to screen blood donors in a tertiary hospital in Kerala for dengue during the period of peak dengue transmission. Materials and Methods: One hundred and seventy-eight continuous serum samples obtained from asymptomatic blood donors during the monsoon season were subjected to ELISA for Dengue NS1 antigen and dengue immunoglobulin M (IgM) antibodies. Results: Dengue IgM antibodies were positive in 20 (11.23%) donors and NS1 antigen was positive in 1 (0.56%) donor. The presence of these markers in asymptomatic blood donors showed that they may have had active or subclinical dengue infection at the time of donation or in the recent past. The presence of NS1 in particular raises the possibility that the donor may have been viremic at the time of donation. Conclusion: The findings of this study suggest the risk of transfusion transmission of dengue during the monsoon in Kerala and strengthen the case for dengue screening among blood donors during this period of high incidence.

   Abstract in French 

Objectif: L'objectif de cette étude était de dépister la dengue chez les donneurs de sang dans un hôpital tertiaire du Kerala pendant la période de transmission maximale de la dengue. Matériels et méthodes: Cent soixante-dix-huit échantillons de sérum continus provenant de donneurs de sang asymptomatiques pendant la saison de la mousson ont été soumis à un test ELISA pour l'antigène de la dengue NS1 et les anticorps de l'immunoglobuline M de la dengue (IgM). Résultats: les anticorps IgM contre la dengue étaient positifs chez 20 (11,23 %) donneurs et l'antigène NS1 était positif chez 1 (0,56 %) donneur. La présence de ces marqueurs chez les donneurs de sang asymptomatiques a montré qu'ils pouvaient avoir eu une infection active ou subclinique de la dengue au moment du don ou dans un passé récent. La présence de NS1 en particulier soulève la possibilité que le donneur ait pu être virémique au moment du don. Conclusion: Les résultats de cette étude suggèrent le risque de transmission transfusionnelle de la dengue pendant la mousson au Kerala et renforcent les arguments en faveur du dépistage de la dengue chez les donneurs de sang pendant cette période de forte incidence.
Mots-clés: Donneurs de sang, dengue, anticorps immunoglobuline M, Kerala, antigène NS1, séropositivité

Keywords: Blood donors, dengue, immunoglobulin M antibody, Kerala, NS1 antigen, seropositivity

How to cite this article:
Raj A R, Shashindran N, Shenoy V, Kumar A. Dengue seropositivity among blood donors in a tertiary hospital in Kerala, Southern India. Ann Afr Med 2022;21:39-42

How to cite this URL:
Raj A R, Shashindran N, Shenoy V, Kumar A. Dengue seropositivity among blood donors in a tertiary hospital in Kerala, Southern India. Ann Afr Med [serial online] 2022 [cited 2023 Mar 22];21:39-42. Available from:

   Introduction Top

Dengue is an arboviral disease whose incidence has surged in recent years in concert with increasing globalization and climate change. A recent study presented a preliminary estimate that 3.9 billion people, in 128 countries the world over, are at risk of dengue.[1] Another estimate suggested that India accounted for 34% of the burden of global dengue in 2010.[2] Dengue is endemic in most of India. The prevalence of four dengue serotypes DEN-1, DEN-2, DEN-3, and DEN-4 has been recorded in Kerala. The mosquito vector Aedes albopictus is widespread in the state.[3] The incidence of dengue in Kerala typically peaks during seasonal outbreaks between May and July during the monsoon season when rainfall is copious.[3]

Several instances of transmission of dengue from asymptomatic donors through transplants and blood transfusions have been recorded.[4-6] Transfusion-transmitted dengue (TTD) is nevertheless a rare entity.[7] Karim et al.[8] in 2017 reported a case where two surgical patients acquired possible TTD from different components obtained from an infected donor. A study conducted in two cities in Brazil during a massive DEN-4 epidemic in 2012 concluded that, during peak periods of transmission in dengue epidemics, as many as, 1%–2% of donations may be positive for dengue viral RNA and 0.3%–0.6% of all transfusions may transmit the virus.[9]

There is no data from southern India regarding dengue seropositivity among blood donors. The present study was undertaken to detect dengue seropositivity among blood donors in a 1350-bedded hospital in Kerala as a preliminary step toward assessing the need for donor screening in a dengue hyperendemic region during the peak transmission period.

   Materials and Methods Top

Information on peak incidence of dengue was derived from dengue statistics in our hospital. The number of cases was found to peak in the month of June, during the monsoon. Hence, the study was done prospectively with 178 continuous serum samples obtained from all asymptomatic blood donors who donated blood at our tertiary hospital in the last 2 weeks of June and consented to participate in the study. The sample size was limited by the cost of the testing kits. Institute ethics committee clearance was obtained prior to the commencement of the study. Eligible donors were questioned carefully to rule out recent history of fever. Those samples that tested positive for HIV, hepatitis B virus, hepatitis C virus, malarial antigen, or syphilitic antibodies during routine blood bank screening were excluded.

Four microliter of peripheral blood were collected in tubes without anticoagulant. The tubes were centrifuged at 3000 rpm for 15 min to obtain serum. Sera were then stored in a deep freezer at − 20°C.

NS1 antigen of dengue virus was assayed using two commercial NS1 antigen capture enzyme-linked immunosorbent assays (ELISAs) (Panbio Dengue Early ELISA, and QUALISA Dengue NS1 ELISA).

Anti-dengue immunoglobulin M (IgM) antibodies were detected using commercial IgM capture ELISA (NovaLisa, NOVATEC Immunodiagnostica,).

The samples were tested in accordance with the manufacturer's instructions. Equivocal results were considered negative.

   Results Top

Blood samples were collected from 178 donors aged between 18 and 60 years. Of these, 89 (50%) were aged between 21 and 30 years and 168 (94.4%) were male. Twenty (11.2%) sera were positive for dengue IgM and one (0.6%) tested positive for NS1 antigen [Table 1]. There was no sample that tested positive for both NS1 antigen and IgM antibody.
Table 1: Dengue immunoglobulin M and nonstructural protein 1 positivity among blood donors

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Twelve (57.1%) of the 21 asymptomatic donors who tested seropositive for dengue were aged between 18 and 30 years [Table 2]. Twelve (57.1%) of the 21 donors who tested positive were residents of Ernakulam district in Kerala, India.
Table 2: Age distribution of blood donors

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There were no signs of transfusion-transmitted illness in the patients who were transfused with the IgM-positive units. The recipients were not tested for dengue. The fate of the blood unit from the donor who tested NS1-positive was traced on the completion of the study to look for evidence of transfusion transmission. It was found that the unit had been discarded, not transfused, even though the fact of NS1 positivity had not been known at the time of discarding.

   Discussion Top

Dengue has an incubation period of 4–10 days.[10] Viremia can precede the onset of fever by 2–3 days and can last up to 8 days after illness onset.[11] The Centers for Disease Control advises that as many as 50% of all dengue infections are asymptomatic.[12] The proportion of dengue infections that are asymptomatic differs both geographically and from one dengue serotype to the other. The level of viremia in asymptomatic as compared to symptomatic dengue infections has not been studied widely, though viremia has been assumed to be lower in asymptomatic infections in some studies.[13]

A PubMed search using the terms “dengue,” “blood donors,” and “India” revealed 2 studies from northern India and 1 from western India on dengue seropositivity in blood donors. There was no data from the southern part of the country. The present study aimed at estimating the rates of dengue seropositivity among asymptomatic blood donors in a tertiary hospital in Kerala, a southern Indian state, as a pilot study, with a view to assessing the risk of transfusion transmission during the monsoon season. Twenty-one (11.7%) out of 178 asymptomatic donors were seropositive. Of these, 20 donors (11.2%) tested dengue IgM positive, suggesting either active infection or infection that occurred within the preceding 3 months. The rate of dengue IgM positivity in this study (11.2%) is similar to that (13.5%) detected in a study in northern India that involved 200 blood donors.[14]

There was one donor (0.56% of all donors) who tested NS1-positive in the present study. The presence of antigenemia in this donor is significant as it implies recent infection and the potential to transmit the virus. Mangwana[15] looked for NSI antigenemia among 1708 blood donors in a study conducted in a tertiary care center in north India and found none positive.

NS1 antigen can be detected from the day of illness onset and can persist up to 18 days.[16] The period of antigenemia overlaps the period of viremia. However, the sensitivity of NS1 declines in secondary dengue infections.[17] NS1 antigen has been postulated to play a role in the replication of dengue virus.[18] Several studies report that dengue viral loads and disease severity are higher among NS1-positive patients.[19],[20],[21]

The seroprevalence of dengue among blood donors has been reported from several studies worldwide. El-Shemi et al. reported a seropositivity of 5.3% for dengue NS1 antigen, 5.5% for dengue IgM antibody, and 38.9% for dengue IgG antibody among blood donors in Makkah, Saudi Arabia.[22]

Aubry et al. studied the presence of IgG against each of the four dengue serotypes in 593 donors in French Polynesia using an indirect ELISA which employed recombinant envelope glycoprotein antigens. They found that DEN-1 seroprevalence was the highest and that 80.3% of the donors had antibodies against one or the other serotype.[23]

A limitation of the present study includes the lack of molecular confirmation of viremia among donors. The confirmation of viremia among blood donors by nucleic acid detection and its quantification by viral load assay would strengthen the case for screening for dengue among blood donors in outbreak situations.

Transfusion transmission is a looming threat during dengue epidemics. There are several proven cases of TTD recorded in literature.[7],[9] Yet dengue is not considered enough of a risk to transfusion safety to warrant routine screening.

Sabino et al., in a study of blood transfusions during a dengue epidemic in Brazil, reported that only a third of the dengue-positive transfusions transmitted the virus.[9] Most recipients of TTD who went on to manifest clinical symptoms have had benign courses of the illness. However, instances of severe dengue with hemorrhagic manifestations have been reported.[4],[7],[24] The American Association of Blood Banks Committee recently included dengue, among other emerging infectious agents such as vCJD, hepatitis E virus, Chikungunya virus, and Babesia as high priority for increased monitoring in American blood supply.[25]

The benefits of pathogen Inactivation systems were convincingly demonstrated by the use of the intercept technology for platelets during the Chikungunya outbreak in Reunion Island in 2006 and the recent Zika virus outbreak in north and south America.[26] As the number of recognized transfusion-transmissible pathogens increases, the adoption of pathogen inactivation methods may eventually prove more economical than expanding the number of tests for donor screening.[27] But, for the moment, many blood banks in developing countries cannot afford the implementation of these technologies.

Deferral measures for donors with history of fever are practised in countries such as Australia, New Zealand, Singapore, and Hong Kong and Sri Lanka. These measures do not preclude transfusion transmission from viremic donors who may be asymptomatic. They have found to be less feasible in dengue-endemic countries when compared to nonendemic countries as their lack of specificity in endemic countries would lead to an unwarranted loss of donors.[6]

   Conclusion Top

Considering these facts and the unavailability of antiviral drugs against dengue, proactive measures must be taken to ensure blood safety. Routine screening for dengue among blood donors is not the norm as it is not cost-effective. However, in the light of the substantial numbers of seropositive blood donors detected during the peak dengue season in Kerala, screening for dengue during these spells may be prudent in this hyperendemic area to prevent transfusion-transmitted infections.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Brady OJ, Gething PW, Bhatt S, Messina JP, Brownstein JS, Hoen AG, et al. Refining the Global spatial limits of dengue virus transmission by evidence-based consensus. PLoS Negl Trop Dis 2012;6:e1760.  Back to cited text no. 1
Bhatt S, Gething PW, Brady OJ, Messina JP, Farlow AW, Moyes CL, et al. The global distribution and burden of dengue. Nature 2013;496:504-7.  Back to cited text no. 2
Kumar NP, Jayakumar PR, George K, Kamaraj T, Krishnamoorthy K, Sabesan S, et al. Genetic characterization of dengue viruses prevalent in Kerala State, India. J Med Microbiol 2013;62:545-52.  Back to cited text no. 3
Tan FL, Loh DL, Prabhakaran K, Tambyah PA, Yap HK. Dengue haemorrhagic fever after living donor renal transplantation. Nephrol Dial Transplant 2005;20:447-8.  Back to cited text no. 4
Gupta RK, Gupta G, Chorasiya VK, Bag P, Shandil R, Bhatia V, et al. Dengue virus transmission from living donor to recipient in liver transplantation: A case report. J Clin Exp Hepatol 2016;6:59-61.  Back to cited text no. 5
Teo D, Ng LC, Lam S. Is dengue a threat to the blood supply? Transfus Med 2009;19:66-77.  Back to cited text no. 6
Pozzetto B, Memmi M, Garraud O. Is transfusion-transmitted dengue fever a potential public health threat? World J Virol 2015;4:113-23.  Back to cited text no. 7
Karim F, Nasir N, Moiz B. Transfusion transmitted dengue: One donor infects two patients. Transfus Apher Sci 2017;56:151-3.  Back to cited text no. 8
Sabino EC, Loureiro P, Lopes ME, Capuani L, McClure C, Chowdhury D, et al. Transfusion-transmitted dengue and associated clinical symptoms during the 2012 epidemic in Brazil. J Infect Dis 2016;213:694-702.  Back to cited text no. 9
Dengue and Severe Dengue. World Health Organization. Available from: [Last accessed on 2018 Jul 25].  Back to cited text no. 10
Tang KF, Ooi EE. Diagnosis of dengue: An update. Expert Rev Anti Infect Ther 2012;10:895-907.  Back to cited text no. 11
Clinical Guidance | Dengue | CDC. Available from: [Last accessed on 2018 Jul 27].  Back to cited text no. 12
Chastel C. Eventual role of asymptomatic cases of dengue for the introduction and spread of dengue viruses in non-endemic regions. Front Physiol 2012;3:70.  Back to cited text no. 13
Ranjan P, Natarajan V, Bajpai M, Gupta E. High seroprevalence of dengue virus infection in blood donors from Delhi: A single centre study. J Clin Diagn Res 2016;10:C08-10.  Back to cited text no. 14
Mangwana S. Dengue viremia in blood donors in Northern India: Challenges of emerging dengue outbreaks to blood transfusion safety. Asian J Transfus Sci 2015;9:177-80.  Back to cited text no. 15
[PUBMED]  [Full text]  
Xu H, Di B, Pan YX, Qiu LW, Wang YD, Hao W, et al. Serotype 1-specific monoclonal antibody-based antigen capture immunoassay for detection of circulating nonstructural protein NS1: Implications for early diagnosis and serotyping of dengue virus infections. J Clin Microbiol 2006;44:2872-8.  Back to cited text no. 16
Levi JE. Dengue virus and blood transfusion. J Infect Dis 2016;213:689-90.  Back to cited text no. 17
Mackenzie JM, Jones MK, Young PR. Immunolocalization of the dengue virus nonstructural glycoprotein NS1 suggests a role in viral RNA replication. Virology 1996;220:232-40.  Back to cited text no. 18
Avirutnan P, Punyadee N, Noisakran S, Komoltri C, Thiemmeca S, Auethavornanan K, et al. Vascular leakage in severe dengue virus infections: A potential role for the nonstructural viral protein NS1 and complement. J Infect Dis 2006;193:1078-88.  Back to cited text no. 19
Thomas L, Najioullah F, Verlaeten O, Martial J, Brichler S, Kaidomar S, et al. Relationship between nonstructural protein 1 detection and plasma virus load in Dengue patients. Am J Trop Med Hyg 2010;83:696-9.  Back to cited text no. 20
Libraty DH, Young PR, Pickering D, Endy TP, Kalayanarooj S, Green S, et al. High circulating levels of the dengue virus nonstructural protein NS1 early in dengue illness correlate with the development of dengue hemorrhagic fever. J Infect Dis 2002;186:1165-8.  Back to cited text no. 21
El-Shemi A, Alghamdi S, Almdani S, Refaat B, Mohamed A, Ghazi OH, et al. Seroprevalence of asymptomatic dengue virus infection and Its antibodies among healthy/eligible Saudi blood donors: Findings from holy Makkah City. Virol Res Treat 2017;8:1-5.  Back to cited text no. 22
Aubry M, Finke J, Teissier A, Roche C, Broult J, Paulous S, et al. Seroprevalence of arboviruses among blood donors in French Polynesia, 2011-2013. Int J Infect Dis 2015;41:11-2.  Back to cited text no. 23
Stramer SL, Linnen JM, Carrick JM, Foster GA, Krysztof DE, Zou S, et al. Dengue viremia in blood donors identified by RNA and detection of dengue transfusion transmission during the 2007 dengue outbreak in Puerto Rico. Transfusion 2012;52:1657-66.  Back to cited text no. 24
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  [Table 1], [Table 2]


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