Rabies Postexposure Management of Travelers Presenting to Travel Health Clinics in Auckland and Hamilton, New Zealand

DOI: http://dx.doi.org/10.1111/j.1708-8305.2008.00256.x 13-17 First published online: 1 January 2009


Background Rabies is a fatal disease, and travelers going to endemic areas need to take precautions. Little is known about the rabies postexposure management of travelers from New Zealand.

Methods A total of 459 post‐travel records from October 1998 until February 2006 at two travel medicine clinics, in Auckland and Hamilton, were examined for those who reported postexposure management to animals while abroad.

Results Fifty‐four patients were included, 48 (88.9%) were New Zealand residents and 52.0% were male. The mean age of exposed travelers was 30.4 years (SD = 15.5). There was an adult to child ratio of 5:1. The highest exposure risk group was those aged 16 to 30 years. South and Southeast Asia were the most prominent geographical regions where exposure occurred, with 45 (83.3%) of subjects being potentially exposed to rabies. Dogs were the commonest animals involved, accounting for two thirds of incidents (36; 66.7%). The commonest sites of animal exposure on the body were the thigh and lower leg (26; 48.1%) and the hand (10; 18.5%). Forty‐six (85.2%) of the animal exposures were graded as World Health Organization (WHO) category III. Forty‐nine (90.7%) of the travelers had not had preexposure prophylaxis. Once in New Zealand, the correct WHO postexposure prophylaxis regime was applied on 44 of 52 (84.6%) occasions. However, overall, only 25% of the sample received postexposure treatment consistent with WHO guidelines, reflecting inappropriate management abroad.

Conclusions Post‐travel consultations at two New Zealand travel clinics were analyzed for prophylactic rabies postexposure management. The majority were travelers aged 16 to 30 years, who sustained WHO category III exposures to the lower limb in Asia, predominantly from dogs. Few of these travelers had been immunized prior to travel, and only 25% of them received postexposure prophylaxis consistent with WHO guidelines. Thus, 75% of the study sample remains at theoretical risk of contracting rabies due to inappropriate management overseas.

Rabies is an acute fatal encephalitis caused by neurotropic viruses in the genus Lyssavirus, family Rhabdoviridae. 1 The disease is found globally, with more than 100 countries reporting the disease. 1 Rabies has never been reported in New Zealand. 2 Of the 40,000 to 70,000 deaths reported annually, about 90% are in Asia. 3 It is widely agreed, however, that the true incidence of human rabies is much higher than this, perhaps up to 100 times greater. 4 This figure is alarming with the realization that misdiagnosis of this disease, eg, with cerebral malaria, plays an important part in its underreporting. 5

The virus is typically transmitted via a skin‐penetrating mammalian bite, but transmission of the virus may also occur via saliva‐contaminated scratches or mucous membranes or rarely by aerosol 6 or through organ transplant. 7 While all mammals are potentially susceptible, carnivores and bats act as reservoirs, 8 and more than 95% of fatal cases are attributable to dog bites. 9 Annually, more than 10 million people are exposed to potentially rabid animals. 10 The risk of acquiring fatal rabies subsequent to exposure to a rabid animal is approximately 15%, ranging from as low as 0.1% in persons experiencing nonbite exposures to as high as 60% in persons with deep wounds or severe injuries. 11

Lesions in exposed individuals who carry a higher risk of acquiring the disease are multiple or deep bites, those on the head, neck, and hand and those in children. 12 The risk of developing rabies can be reduced to near zero with thorough wound cleansing, including the use of soap, povidone–iodine, and the appropriate postexposure prophylaxis. 13

The World Health Organization (WHO) has approved three postexposure vaccination regimes 14 for those who have had no preexposure prophylaxis, with vaccines that are of a cell‐derived tissue culture: human diploid cell vaccine (HDCV), purified vero cell vaccine, and purified primary chick embryo cell vaccine. 15 In New Zealand, the current vaccine is the HDCV, and an intradermal series of three costs around $US130. Vaccines of nervous tissue origin are still used in a small number of developing countries, but they are not recommended due to a high risk of neurological side effects and low potency of the vaccine. 10

Passive immunization with rabies immunoglobulin (RIG) is additionally recommended for high‐risk, or immune‐compromised, exposures in those previously unimmunized at the initial presentation. 16 The WHO has categorized the degree of exposure to animal contacts as an aid to management of the exposure (see Table 1). Human rabies immunoglobulin (HRIG) is mainly available in industrialized countries while both purified equine rabies immunoglobulin (ERIG) and human immunoglobulin are used in developing countries. F(ab′)2 (the portion of the immunoglobulin or antibody molecule that contains the binding site for antigens) products have recently been developed from equine immunoglobulins. Clearance of F(ab′)2 fragments is more rapid than that of intact immunoglobulins, so that in case of multiple severe exposures, HRIG should preferably be used for passive immunization. Nevertheless, RIG should be administered to all category III exposures (as well as immunocompromised patients with category II exposures). 17 While HRIG is the preference, ERIG is now highly purified, and the occurrence of side effects is now significantly reduced. Thus, if cost is an issue, then ERIG is acceptable first‐line management of animal exposure. Those who have been previously immunized against rabies (preexposure prophylaxis) do not require HRIG and simply need booster vaccinations on days 0 and 3. 16

View this table:
Table 1

World Health Organization categories of rabies exposure 9

Category I (mild injury)Touching or feeding of animals; licks on intact skin but no penetration of the skin
Category II (moderate injury)Chewing of uncovered skin; minor scratches or abrasions without bleeding; licks on broken skin
Category III (severe injury)Single or multiple transdermal bites or scratches; licks on broken skin or mucous membranes; contact with bats

In the Pacific Rim area, New Zealand, Australia, Papua New Guinea, the Pacific Islands, and Japan are considered rabies free. 18 Therefore, the only situation where rabies postexposure prophylaxis could be required in New Zealand is when a traveler, or immigrant, presents locally after an exposure in an endemic country. Both the WHO 19 and the Centers for Disease Control and Prevention (CDC) 20 recommend that those who are likely to be exposed to rabies when traveling to endemic areas should be offered preexposure immunization.

A recent epidemiological study of travelers presenting to GeoSentinel (a collaborative surveillance program between the CDC and the International Society of Travel Medicine) sites worldwide found that 4.7% of this population required postexposure prophylaxis against rabies (rate of 46 per 1,000 travelers). 21 The GeoSentinel site in New Zealand, monitoring post‐travel health concerns, reported a high 8% of the patient population presenting for rabies postexposure prophylaxis. 22

This study sought to describe the demographics and postexposure management of travelers presenting to two New Zealand dedicated travel health clinics for postexposure rabies prophylaxis between 1998 and 2006. Analysis of such data could suggest a reason for the high rate of recently traveled New Zealanders who present with potential lethal rabies exposure.

To our knowledge, this is the first such study in New Zealand. A literature search revealed few epidemiological studies of postexposure prophylaxis in a rabies‐free setting, with most conducted in endemic locations globally. 23–27 While the target populations were mostly locals, expatriates, or military personnel in an endemic country, we could find no published data on postexposure prophylaxis in clinics specifically dedicated to the health of returned travelers.


While the target population was primarily identified as (1) New Zealanders who travel overseas to rabies‐endemic regions, also included would be (2) non‐New Zealand resident travelers who travel to rabies‐endemic regions as well as to New Zealand during the same period of travel.

All patients presenting to dedicated travel health clinics in either Auckland or Hamilton between October 1998 and February 2006 for consideration of postexposure rabies management, including prophylaxis, following a potential exposure to rabies infection during travel were included in this study.

The “post‐travel consultations” patient database was retrospectively examined at both the Auckland and the Hamilton clinics to identify cases meeting the inclusion criteria. A total of 459 travelers presented to a dedicated travelers health center in either Auckland or Hamilton from October 1998 until the end of February 2006.

Data were collected on the following:

  • Gender

  • Country and world region where exposure occurred

  • Age of subject exposed

  • Animal related to the exposure

  • Site of exposure on the body

  • WHO category of exposure (Table 1)

  • Preexposure prophylaxis status

  • Postexposure immunoglobulin given

  • Postexposure vaccine given

  • Type of postexposure vaccination regime and whether it was WHO approved

  • Presence or absence of travel health insurance.

The data were entered in tabulated form into Microsoft Excel. It was submitted to simple statistical analysis with the aid of a scientific calculator.


A total of 54 patients were included in this study or about 0.8 patients per month for the study period. Four patients with inconclusive records were excluded. The demographic characteristics of the sample have been summarized in Table 2. Most patients (48; 88.9%) were New Zealand residents and 6 (11.1%) were not. The male to female ratio was 1.1:1. The mean age of exposed travelers was 30.4 years (SD = 15.5). The highest exposure risk group was the 16 to 30 years age group. There was an adult to child ratio of 5:1. Eight of the nine children were younger than 8 years, with the other being 12 years old.

View this table:
Table 2

Demographic characteristics of the travelers potentially exposed to rabies

Age group (y)
 New Zealand resident4888.9
 Non‐New Zealand resident611.1

Southeast Asia was the most prominent geographical region where exposure occurred, with 45 (83.3%) of subjects being potentially exposed to rabies. The commonest countries where exposure occurred were Thailand, 19 (35.2%); India, 10 (18.5%); Vietnam, 4 (7.4%); and Indonesia, 3 (5.6%). Travelers to Central and South America were next most at risk with five (9.3%) of the animal exposures. The commonest country for exposure in this region was Peru with three (5.6%). African travelers accounted for only three (5.6%) cases.

The commonest animals involved were dogs, which accounted for two thirds of incidents (36; 66.7%). Other animals involved included monkeys (10; 18.5%), cats (4; 7.4%), bats (1; 1.9%), tigers (1; 1.9%), and unspecified (1; 1.9%).

The commonest sites of animal exposure on the body were the thigh and lower leg (26; 48.1%) and the hand (10; 18.5%), together accounting for two thirds of the sites. Other sites included chest or back (2; 3.7%), face (1; 1.9%), foot (1; 1.9%), and perineum (1; 1.9%). The categories of animal exposures to the subjects were graded as category I (0; 0%), category II (6; 11.1%), category III (46; 85.2%), and unknown (2; 3.7%).

Most of the travelers (49; 90.7%) did not have preexposure prophylaxis. A small number had preexposure prophylaxis (3; 5.6%), and the status was unknown for two (3.8%) subjects. Nearly three quarters (33 of 46; 71.2%) of those who sustained a category III exposure and qualified for HRIG, by way of the WHO criteria, had not received it acutely and presented in New Zealand too late for its administration. 20.4% correctly received timely HRIG. Of these, 3 of 11 (27%) were administered HRIG appropriately according to WHO criteria (ie, 20 IU/kg subcutaneously into the wound and into the nearest large muscle mass) in New Zealand travel medicine clinics and one patient was likewise appropriately ministered to in the United States. Thus, 4 of 11 (36%) were documented as having correctly been given HRIG. The remaining seven were administered RIG abroad, and it was unclear from overseas documentation whether this was appropriately administered.

The correct regime, using appropriate vaccine and HRIG according to WHO standards, was started overseas on only 14 (25.9%) occasions. Of additional concern was that the incorrect regime was initiated in more than two thirds (38; 70.4%) of cases while traveling. Additionally, two subjects had a variation of both correct and incorrect regimes.


While a total of 54 travelers were seen at specialized travel medicine clinics in Auckland and Hamilton for a 7‐year period, equating to 9 to 10 cases per year, this number probably is an underestimate of the true incidence of postexposure prophylaxis in New Zealand. Exposed travelers may have presented at other national medical centers, eg, hospital emergency departments, for postexposure prophylaxis. That this number is underestimated is reinforced by figures from other industrialized nations such as Europe where 50,742 individuals were given rabies postexposure prophylaxis in 1997 13 and in the United States where it is estimated that 25,000 to 40,000 people receive postexposure prophylaxis annually. 28 Without knowledge of the number of travelers who present for follow‐up of animal exposure on return to this country, it is difficult to make direct comparisons with the figures above; nevertheless, a recent survey of 23,509 ill travelers returning to specialist travelers’ health centers revealed that 1.4% of them had been exposed to animal‐related injuries. 29

Children aged 5 to 15 years are the most affected by rabies, representing their lack of inhibitions and inability to often protect themselves against attack from exposed animals. 13 This group made up nearly one fifth of this data set. They are a significant potential risk group for rabies exposure and need pretravel health advice.

The fact that most exposures occurred in Asia probably reflects the popularity of the region as a travel destination. In the year ending September 2007, 243,504 visitors from New Zealand traveled there. 30 Thailand accounted for more than one third of the total exposures within the study, with India, Vietnam, and Indonesia following in decreasing incidence. Canine rabies is highly endemic in Asia and the Indian subcontinent, 4 and the implication is that the majority of exposures in New Zealand travelers occurred in rabies‐endemic areas.

The animals that subjects were most frequently exposed to were dogs, accounting for two thirds of the exposures; monkeys accounted for around 20% of all exposures. This finding is in keeping with the fact that dogs are the primary agents of the disease spread in developing countries. 4

Half of the exposures occurred on the lower limb, which is generally considered a low‐risk site due to its lack of proximity to the central nervous system. About one fifth of exposures were located on the hand, considered high risk due to the high density of nerve endings in this region, and 1.9% occurred on the face, which is similarly of high risk. The site of exposure was unrecorded in 15.1% of cases and audited for future analysis.

85.3% of exposures were WHO category III, high risk. Only three travelers (5.6%) had received preexposure prophylaxis. In two travelers, the preexposure vaccination status was understood to have been checked but not documented. Postexposure vaccination was administered to 96.3% of subjects. In the two in whom it was not given, one had been previously vaccinated and the exposure at the time was deemed insignificant and the other was bitten by a domestic animal understood to have been healthy and vaccinated against rabies. The WHO advises observation of the animal after a category III dog bite exposure for 10 days. 31 This is, however, an impractical solution for travelers who are necessarily mobile in their travels. Pretravel advice and early appropriate postexposure management are much more practical alternatives.

RIG was received by only 20.4% of the sample. Of this number, 36% were documented as having correctly been given HRIG into the wound, with the remainder being given HRIG into the nearest muscle mass. Alarmingly, 71.2% had category III exposures and therefore, according to WHO criteria, should have received immunoglobulin and did not, thereby increasing their risk of fatal encephalomyelitis. All these cases had commenced their postexposure vaccine regimes by the time they attended the clinics in New Zealand, and the 7‐day window period for immunoglobulin administration had already elapsed. This disturbing statistic is probably a reflection of (1) the lack of availability of immunoglobulin in developing countries; (2) the lack of the traveler’s knowledge of the disease; and (3) the lack of the local health practitioner’s awareness of its necessity. Only 5.6% of those exposed had received rabies preexposure prophylaxis, which eliminates the need for immunoglobulin after a category III exposure.

In a Swiss study of 72 animal bites among Swiss and German expatriates in the tropics in 1995, 27 only 24% to 30% of postexposure treatments were in accordance with WHO guidelines, which is a similar rate to the 25.9% seen in this study.

While appropriate postexposure treatment, including either HRIG or ERIG, is usually available in most of the major centers in Asia where animal bites are most common, eg, Bangkok and Kathmandu, travelers need to be made aware of current availability in the regions they will be visiting. Ideally, this should be done at pretravel consultation, and as many travelers may not consult with a travel health professional before venturing abroad, then other means of media promotion should be realized. Often, payment for postexposure vaccination regimes is expensive overseas but is usually covered by health insurance. Travel health insurance was recorded as being possessed by only 26% of travelers. For the remainder of the sample, its presence or absence had not been recorded. There is an ongoing need to encourage travelers to invest in travel insurance for their full travel itinerary. 32

Limitations of this study mainly relate to access to relevant data. Four sets of patient records were inappropriately recorded, necessitating their exclusion from the study. This may have some effect on the relatively small sample analyzed. In other sets of records, there were occasional significant omissions, cause for audit, and review of practice standards. The retrospective nature of the study predestined limited analysis on the data recorded at the time of presentation. This included a precise analysis of time delay between potential rabies exposure and the initiation of treatment, which was not a particular focus of this study. The reader is referred for additional information on this important condition to the WHO Expert Consultation on Rabies. 33


A considerable proportion of post‐travel consultations at two New Zealand travel clinics were for postexposure rabies treatment following exposures while traveling in endemic countries. Most of these were younger travelers in the 16 to 30 years age group, who sustained category III exposures to the lower limb in Asia, predominantly from dogs. Very few travelers had been immunized prior to their travel, and only a quarter of the cohort bitten overseas received initial postexposure treatment consistent with WHO guidelines. The risk of rabies in children younger than 8 years, who are at particular risk for animal bites, requires particular attention, especially as this group represented nearly one fifth of cases in this study. It is important that travelers from New Zealand are made aware of the risks of developing rabies secondary to animal exposure in countries they travel to. All travelers need to obtain adequate pretravel health advice on the prevention of a disease that is virtually 100% fatal from a qualified travelers’ health source.

Declaration of interests

P. A. L. is a member of the Australian Travel Health Advisory Group, which receives an unrestricted educational grant from GlaxoSmithKline. The other authors state that they have no conflicts of interest.


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