Seroprevalence of seven zoonotic pathogens in pregnant women from the Caribbean

WOOD AND OTHERS

SEROPREVALENCE OF ZOONOSES IN THE CARIBBEAN

Short Report: Seroprevalence of Seven Zoonotic Pathogens in Pregnant Women

from the Caribbean

Heidi Wood,* Michael A. Drebot, Eric Dewailly, Liz Dillon, Kristina Dimitrova, Martin Forde,

Allen Grolla, Elise Lee, Amanda Loftis, Kai Makowski, Karen Morrison, Lyndon Robertson,

and Rosina C. Krecek

National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada; University of

Laval, Quebec City, Quebec, Canada; St. George’s University, St. George’s, Grenada; Ross University School of

Veterinary Medicine, Basseterre, St. Kitts; Ontario Veterinary College, University of Guelph, Guelph, Ontario,

Canada; Caribbean EcoHealth Programme, St. George’s, Grenada

* Address correspondence to Heidi Wood, 1015 Arlington Street, Winnipeg, Manitoba, Canada, R3E 3R2. Email:

[email protected]

Abstract.

Studies examining the prevalence of zoonotic agents in the Caribbean are very limited. The objective of this study

was to examine the seroprevalence of seven zoonotic agents among individuals residing on 10 English-speaking

Caribbean countries. Sera from healthy, pregnant women were collected from Antigua-Barbuda, Belize, Bermuda,

Dominica, Grenada, Jamaica, Montserrat, St. Kitts-Nevis, St. Lucia, and St. Vincent-Grenadines and tested for the

presence of IgG antibodies to dengue virus, hepatitis E virus, hantaviruses, leptospiral agents, spotted fever group

rickettsiae (SFGR), typhus group rickettsiae (TGR), and Coxiella burnetii (Q fever). The highest seroprevalence

values were observed for dengue virus, SFGR, and leptospirosis, although the lowest seroprevalence values were

observed for hepatitis E virus, C. burnetii, and TGR. Antibodies to hantaviruses were not detected in any

individuals.

INTRODUCTION

The epidemiology of zoonotic infections within the Caribbean region is currently poorly

understood. A limited number of studies have focused on zoonotic pathogens of humans and

livestock and include a review of tick-borne transmission of rickettsial agents and studies on

Rickettsia africae in livestock on eight Caribbean islands.1,2

Other studies have identified dengue

virus (a mosquito-borne arbovirus) and leptospirosis as emerging health problems.3–6

Limited

cases of zoonotic hepatitis E virus (HEV) infection have been documented but only preliminary

characterization has been performed.7 The objective of this study was to examine the

seroprevalence of seven zoonotic agents among individuals residing in 10 Caribbean countries.

METHODS

From 2009 to 2011, blood samples were collected from up to 50 healthy, pregnant women

from the following countries: Antigua-Barbuda, Belize, Bermuda, Dominica, Grenada, Jamaica,

Montserrat, St. Kitts-Nevis, St. Lucia, and St. Vincent-Grenadines.8 This study was approved by

the ethics committees of St. George’s University, Grenada and the University of Laval, Quebec,

Canada. Informed consent was obtained from all participants. All samples were processed at

Ross University School of Veterinary Medicine (RUSVM) in St. Kitts. A total of 442 serum

samples were tested for antibodies against HEV and leptospiral agents at RUSVM; and for

In order to provide our readers with timely access to new content, papers accepted by the American Journal of Tropical Medicine and Hygiene are posted online ahead of print publication. Papers that have been accepted for publication are peer-reviewed and copy edited but do not incorporate all corrections or constitute the final versions that will appear in the Journal. Final, corrected papers will be published online concurrent with the release of the print issue.

http://ajtmh.org/cgi/doi/10.4269/ajtmh.14-0107The latest version is at Accepted for Publication, Published online June 9, 2014; doi:10.4269/ajtmh.14-0107.

Copyright 2014 by the American Society of Tropical Medicine and Hygiene

antibodies against dengue virus, hantaviruses, spotted fever group rickettsiae (SFGR), typhus

group rickettsiae (TGR), and Coxiella burnetii at the National Microbiology Laboratory in

Canada. Sera were tested for immunoglobulin G (IgG) antibodies using the following kits:

Dengue IgG ELISA (Focus Diagnostics, Cypress, CA), Hantavirus IgG DxSelect kit (Focus

Diagnostics), recombLine HantaPlus IgG kit (Phoenix AirMid Biomedical, Ontario, Canada),

Hepatitis E Virus (HEV) ELISA (MP Biomedicals, Asia Pacific Ltd.), Leptospira biflexa

(serovar patoc 1) Microwell IgG ELISA (Diagnostic Automation, Inc., Calabasas, California),

Panbio Coxiella burnetii (Q fever) IgG ELISA (Alere Inc., Ottawa, Ontario), and Q fever IFA

IgG (Focus Diagnostics). All assays were performed according to the manufacturers’

instructions.

Serum samples were tested for IgG antibodies against SFGR using an in-house indirect

immunofluorescent antibody (IFA) with R. rickettsii antigen and to TGR using R. typhi antigen.9

Serum samples were screened for IgG antibodies to hantaviruses using the Hantavirus IgG

DxSelect kit. Samples that tested positive or equivocal on the commercial enzyme-linked

immunosorbent assay (ELISA) were then tested with an in-house ELISA (using Black Creek

Canal virus as antigen) and the recombLine HantaPlus IgG kit to confirm the results of the

DxSelect kit.10

Serum samples were screened for IgG antibodies to phase II C. burnetii using the

Panbio ELISA kit. Samples that tested positive or equivocal by ELISA were then tested with the

Focus Diagnostics IFA kit to confirm the ELISA results and to determine the end-point titers for

IgG against phase I and II C. burnetii antigens.

RESULTS

The majority of individuals enrolled in this study were positive for IgG antibodies to dengue

virus, with an overall seroprevalence of 83.0 ± 3.5% (Table 1). Seroprevalence values of 90–

100% were observed for all countries except Bermuda (8%.) and Belize (36%). This suggests

that the risk for dengue exposure in these countries may be lower than in the others studied.

Because of the cross-reactive nature of flavivirus antibodies, it is possible that a portion of the

dengue seropositive specimens may be associated with exposure to other flaviviruses. However,

the results from this study are consistent with previous studies indicating extensive circulation of

dengue virus serotypes throughout the Caribbean.6

A high seroprevalence to SFGR was detected throughout the countries studied. Overall, 33.5

± 4.4% of the samples displayed a titer of 64 when Rickettsia rickettsii was used as the antigen.

All samples reactive at a titer of 64 to SFGR were non-reactive against R. typhi antigen,

indicating that the serological response was specific to SFGR. In contrast to SFGR, a very low

seroprevalence of 1.6 ± 1.2% for TGR was detected. However, the seroprevalence of

leptospirosis was 18.6 ± 3.6% overall, with seropositive individuals detected in all countries

studied, suggesting ongoing circulation of Leptospira species throughout the region. The

seroprevalences of HEV (1.4 ± 1.1%) and C. burnetii (2.3 ± 1.4%) were low and no individuals

were seropositive for hantaviruses.

DISCUSSION

This is the first study to examine the seroprevalence of a variety of bacterial and viral

zoonotic agents in inhabitants of 10 Caribbean countries. Overall, the highest seroprevalence

values were documented for dengue viruses, SFGR, and leptospiral agents, whereas lower values

were shown for HEV, TGR, and Q fever, and no individuals were found seropositive for

exposure to hantaviruses (Table 1).

Dengue virus is one of the world’s most important mosquito-borne viruses and the Caribbean

region has experienced a major surge in activity.4–6,11,12

Dengue virus can circulate in sylvatic

cycles involving non-human primates and can therefore be considered zoonotic; however, most

transmission occurs in urban cycles involving only humans and mosquitoes. Nevertheless, the

importance of this virus as a major vector-borne pathogen justified its inclusion in this study and

the high degree of seroprevalence observed is consistent with previous studies showing the

hyperendemic nature of its circulation in the Caribbean. The results from this study agree with a

recent publication on the prevalence of dengue virus antibody in healthy Jamaicans in which

100% of participants were seropositive.13

Leptospirosis is an emerging bacterial zoonosis that has a greater incidence in tropical areas

where conditions for transmission are favorable and many wild and domestic animals serve as

reservoirs.14

Transmission to humans is usually by contact with water contaminated by animal

urine and dengue-like febrile illness may result from infection. The results described here are

consistent with recent studies that indicate that suspect dengue cases may actually be associated

with Leptospira infection and exposure rates may be higher in the Caribbean than previously

believed.3

Coxiella burnetii is endemic worldwide and is transmitted to humans usually by

contamination of the environment with the birth products from infected sheep, goats, or cattle.

Acute Q fever typically presents as a flu-like illness with fever and headache, and some patients

may present with pneumonia or hepatitis.15

In this study, the overall seroprevalence was

determined to be 2.3% among women living in the Caribbean, using a cutoff of 64 for the

determination of seropositivity. Interestingly, our results are consistent with the seroprevalence

of Q fever in the United States, which was determined to be 3.1% among healthy adults,

although the seroprevalence was higher in men (3.8%) than women (2.5%).16

Previous studies have shown that R. africae-infected Amblyomma variegatum ticks are

widespread in the Caribbean. However, only one human serosurvey has been published

involving individuals from the Caribbean.17

In a study conducted in Guadeloupe, 49% of

individuals tested had antibody titers of 50 to R. africae, and the prevalence in men was

significantly higher than in women (66% in men versus 39% in women at a titer of 50).

Seroprevalence values among women in both the serosurvey from Guadeloupe and this study are

consistent (39% versus 33.5%, respectively), suggesting a high rate of exposure to infected tick

vectors within the Caribbean region. These results are also consistent with other studies that have

found a high prevalence of R. africae in Amblyomma variegatum ticks in several Caribbean

countries, such as Guadeloupe, St. Kitts-Nevis, Dominica, Montserrat, St. Lucia, and Antigua,

with infection rates ranging from 7% to over 50% of all A. variegatum ticks tested.1,17–19

A low seroprevalence rate (1.6%) was observed for typhus group rickettsiae, suggesting that

these are not common infections in the Caribbean. R. typhi is the etiological agent of murine

typhus, and is typically transmitted to humans via rat fleas with rodents serving as the primary

reservoir.20

Although considered endemic worldwide, and prevalent in the coastal areas of

tropical and subtropical regions, the results from this study suggest that R. typhi is not a common

zoonotic agent in the countries included in this study.

Hepatitis E is endemic in regions of poor sanitation and has been chiefly associated with

cases in Africa, Asia, the Mediterranean, Mexico and South America.21

Several Caribbean

countries have reported HEV circulation, but viral characterization has been limited.7 Although

the transmission of the virus is primarily fecal–oral through contaminated water, there is also

evidence of zoonotic transmission in certain cases. Recent studies have investigated swine,

including pork meat, as a source of zoonotic hepatitis E infection.22

The results from this study

indicate a low prevalence of antibody in the individuals tested (although the possibility that these

results may represent false-positives cannot be ruled out); however, the possible route(s) of

transmission of this virus requires further study.

Hantaviruses are rodent-borne and contribute to significant numbers of cases associated with

hemorrhagic fever and pulmonary syndromes.23,24

Antibodies to hantaviruses were not detected

in any of the samples analyzed in this study; this is in contrast to a recent study that showed

significant exposure rates among farm and abattoir workers in Trinidad.25

Further investigations

to evaluate the risk for hantavirus infection in the Caribbean are thus warranted.

Received February 17, 2014.

Accepted May 11, 2014.

Authors’ addresses: Heidi Wood, Michael A. Drebot, Liz Dillon, Kristina Dimitrova, Allen Grolla, and Kai

Makowski, Public Health Agency of Canada, Winnipeg, Manitoba, Canada, E-mails: [email protected],

[email protected], [email protected], [email protected],

[email protected], and [email protected]. Eric Dewailly, Laval University, Quebec City,

Quebec, Canada, E-mail: [email protected]. Martin Forde, St. George’s University, St. George’s,

Grenada, E-mail: [email protected]. Elise Lee, University of Florida, Gainesville, FL, E-mail:

[email protected]. Amanda Loftis, Ross University School of Veterinary Medicine, St. Kitts, E-mail:

[email protected]. Karen Morrison, York University, Toronto, Ontario, Canada, E-mail: [email protected].

Lyndon Robertson, Caribbean EcoHealth Programme (CEHP), Windward Islands Research and Education

Foundation (WINDREF), St. George’s, Grenada, E-mail: [email protected]. Rosina C. Krecek, Texas

A&M University, College Station, TX, E-mail: [email protected].

REFERENCES

<jrn>1. Kelly P, Lucas H, Beati L, Yowell C, Mahan S, Dame J, 2010. Rickettsia africae in

Amblyomma variegatum and domestic ruminants on eight Caribbean islands. J Parasitol 96:

1086–1088.</jrn>

<jrn>2. Kelly PJ, 2006. Rickettsia africae in the West Indies. Emerg Infect Dis 12: 224–

226.</jrn>

<jrn>3. Brown MG, Vickers IE, Salas RA, Smikle MF, 2010. Leptospirosis in suspected cases of

dengue in Jamaica, 2002–2007. Trop Doct 40: 92–94.</jrn>

<jrn>4. Mohammed H, Ramos M, Armstrong J, Munoz-Jordan J, Arnold-Lewis KO, Ayala A,

Clark GG, Tull ES, Beatty ME, 2010. An outbreak of dengue fever in St. Croix (US Virgin

Islands), 2005. PLoS ONE 5: e13729.</jrn>

<jrn>5. Hospedales CJ, 1990. Dengue fever in the Caribbean. West Indian Med J 39: 59–

62.</jrn>

<jrn>6. Isturiz RE, Gubler DJ, Brea del Castillo J, 2000. Dengue and dengue hemorrhagic fever

in Latin America and the Caribbean. Infect Dis Clin North Am 14: 121–140.</jrn>

<jrn>7. Villalba Mde L, Lay Lde L, Chandra V, Corredor MB, Frometa SS, Moreno AG, Jameel

S, 2008. Hepatitis E virus genotype 1, Cuba. Emerg Infect Dis 14: 1320–1322.</jrn>

<jrn>8. Forde M, Morrison K, Dewailly E, Badrie N, Robertson L, 2011. Strengthening

integrated research and capacity development within the Caribbean region. BMC Int Health

Hum Rights 11(Suppl 2): S2–S7.</jrn>

<jrn>9. Prabhu M, Nicholson WL, Roche AJ, Kersh GJ, Fitzpatrick KA, Oliver LD, Massung

RF, Morrissey AB, Bartlett JA, Onyango JJ, Maro VP, Kinabo GD, Saganda W, Crump JA,

2011. Q fever, spotted fever group, and typhus group rickettsioses among hospitalized febrile

patients in northern Tanzania. Clin Infect Dis 53: e8–e15.</jrn>

<jrn>10. Ksiazek TG, Peters CJ, Rollin PE, Zaki S, Nichol S, Spiropoulou C, Morzunov S,

Feldmann H, Sanchez A, Khan AS, 1995. Identification of a new North American hantavirus

that causes acute pulmonary insufficiency. Am J Trop Med Hyg 52: 117–123.</jrn>

<jrn>11. Pupo M, Guzman MG, Fernandez R, Llop A, Dickinson FO, Perez D, Cruz R,

Gonzalez T, Estevez G, Gonzalez H, Santos P, Kouri G, Andonova M, Lindsay R, Artsob H,

Drebot M, 2006. West Nile virus infection in humans and horses, Cuba. Emerg Infect Dis 12:

1022–1024.</jrn>

<jrn>12. Prince HE, Matud JL, Lieberman JM, 2011. Dengue virus immunoglobulin M detection

in a reference laboratory setting during the 2010 dengue virus outbreak on Caribbean islands.

Clin Vaccine Immunol 18: 1104–1107.</jrn>

<jrn>13. Brown MG, Vickers IE, Salas RA, Smikle MF, 2009. Seroprevalence of dengue virus

antibodies in healthy Jamaicans. Hum Antibodies 18: 123–126.</jrn>

<jrn>14. Toyokawa T, Ohnishi M, Koizumi N, 2011. Diagnosis of acute leptospirosis. Expert

Rev Anti Infect Ther 9: 111–121.</jrn>

<jrn>15. Tissot-Dupont H, Raoult D, 2008. Q fever. Infect Dis Clin North Am 22: 505–514

ix.</jrn>

<jrn>16. Anderson AD, Kruszon-Moran D, Loftis AD, McQuillan G, Nicholson WL, Priestley

RA, Candee AJ, Patterson NE, Massung RF, 2009. Seroprevalence of Q fever in the United

States, 2003–2004. Am J Trop Med Hyg 81: 691–694.</jrn>

<jrn>17. Parola P, Vestris G, Martinez D, Brochier B, Roux V, Raoult D, 1999. Tick-borne

rickettiosis in Guadeloupe, the French West Indies: isolation of Rickettsia africae from

Amblyomma variegatum ticks and serosurvey in humans, cattle, and goats. Am J Trop Med

Hyg 60: 888–893.</jrn>

<jrn>18. Kelly PJ, Fournier PE, Parola P, Raoult D, 2003. A survey for spotted fever group

rickettsiae and ehrlichiae in Amblyomma variegatum from St. Kitts and Nevis. Am J Trop

Med Hyg 69: 58–59.</jrn>

<jrn>19. Robinson JB, Eremeeva ME, Olson PE, Thornton SA, Medina MJ, Sumner JW, Daschi

GA, 2009. New approaches to detection and identification of Rickettsia africae and Ehrlichia

ruminantium in Amblyomma variegatum (Acari: Ixodidae) ticks from the Caribbean. J Med

Entomol 46: 942–951.</jrn>

<jrn>20. Civen R, Ngo V, 2008. Murine typhus: an unrecognized suburban vectorborne disease.

Clin Infect Dis 46: 913–918.</jrn>

<jrn>21. Aggarwal R, Naik S, 2009. Epidemiology of hepatitis E: current status. J Gastroenterol

Hepatol 24: 1484–1493.</jrn>

<jrn>22. Wilhelm BJ, Rajic A, Greig J, Waddell L, Trottier G, Houde A, Harris J, Borden LN,

Price C, 2011. A systematic review/meta-analysis of primary research investigating swine,

pork or pork products as a source of zoonotic hepatitis E virus. Epidemiol Infect 139: 1127–

1144.</jrn>

<edb>23. Drebot MA, Safronetz D, 2010. Sin nombre virus. Dongyou L, ed. Molecular

Detection of Human Viral Pathogens. CRC Press, Taylor and Francis Group.</edb>

<jrn>24. Bi Z, Formenty PB, Roth CE, 2008. Hantavirus infection: a review and global update. J

Infect Dev Ctries 2: 3–23.</jrn>

<jrn>25. Adesiyun A, Dookeran S, Stewart-Johnson A, Rahaman S, Bissessar S, Thompson N,

2011. Serological evidence of hantavirus infection in farm and abattoir workers in Trinidad–a

preliminary study. J Agromed 16: 194–199.</jrn>

TABLE 1

Seroprevalence of zoonotic pathogens in pregnant women from 10 Caribbean Islands*

Country Zoonotic pathogen seroprevalence ± 95% CI

Dengue virus Hantaviruses Hepatitis E virus Leptospira species SFGR TGR C. burnetii

Antigua-Barbuda 94.7 ± 7.1 ND ND 10.5 ± 9.8 36.8 ± 15.3 ND 5.3 ± 6.6

Belize 36.0 ± 13.3 ND ND 8.0 ± 7.5 54.0 ± 13.8 ND ND

Bermuda 8.0 ± 7.5 ND ND 12.0 ± 9.0 40.0 ± 13.6 ND ND

Dominica 98.0 ± 3.9 ND ND 16.0 ± 10.2 36.0 ± 13.3 2.0 ± 3.9 ND

Grenada 98.0 ± 3.9 ND 2.0 ± 3.8 21.6 ± 11.3 2.0 ± 3.9 2.0 ± 3.8 ND

Jamaica 100.0 ± 0.0 ND 2.1 ± 4.1 42.6 ± 14.1 44.7 ± 14.2 2.1 ± 4.1 2.1 ± 4.1

Montserrat 80.0 ± 20.2 ND ND 20.0 ± 20.2 20.0 ± 20.2 ND 6.6 ± 12.7

St. Kitts-Nevis 100.0 ± 0.0 ND ND 9.1 ± 8.5 43.2 ± 14.2 2.3 ± 4.3 13.6 ± 10.1

St. Lucia 97.0 ± 4.1 ND 2.2 ± 4.2 19.6 ± 11.5 14.9 ± 10.2 2.1 ± 4.1 ND

St. Vincent-Grenadines 94.0 ± 6.6 ND 2.0 ± 3.9 26.0 ± 12.2 36.0 ± 13.3 4.2 ± 5.4 ND

All countries 83.0 ± 3.5 ND 1.4 ± 1.1 18.6 ± 3.6 33.5 ± 4.4 1.6 ± 1.2 2.3 ± 1.4

* CI = confidence interval; ND = not detected.