Why rooster crowing isn’t that impressive, and chickens get jet lag like the rest of us.

Circadian rhythms and jet lag.  There, cyclic crowing behavior explained.

Quite a lot of people are discussing this study from Japan examining the effect of light on the crowing behavior of roosters. The authors observed several birds in experimental conditions where light intensity and duration were controlled, taking observations with audio recorders and cameras. The scenarios presented were a daylight cycle of 12 hours of light and dim light respectively, and constant dim light. Observations were recorded for a period of 14 days, producing this graph.

So many reporters on the study have run with this, making declarations about what great timekeepers roosters are, and how cool it is that they don’t need the sun to know when dawn is.

Well, approximately when dawn is.

“Under dimLL conditions, a free-running rhythm of crowing was observed with a period of 23.7 ± 0.1 h (n = 4), but this free-running rhythmicity gradually damped out”

Interesting, so the sun is unnecessary until it’s been gone for a while, then we start to get some variation. This dampening effect is even more obvious when you place testosterone implants in the roosters (the roosters begin shouting about bro’s and lifting presumably).

Don’t get me wrong, the fact that Roosters have this accurate of a circadian clock is impressive! It’s very interesting biologically, but it’s not some infallible atomic clock. While many news sites are toting that Roosters are independent of the sun, the opposite is true. Circadian rhythms are directly calibrated primarily by light cycling, with temperature being another important environmental cue. To confirm the roosters knew what time it was, the authors examined the effect of light or recorded crowing sounds at different times of day. They found that there were fewer crowing behaviors at random dawn times than at the “correct time” of day.

This doesn’t mean the roosters know it’s 5pm, but their circadian rhythm is telling them that it isn’t dawn. However, the sun still “came up” so we witness some halfhearted crowing. Anyone who has ever traveled out of their timezone knows exactly how this feels: these roosters have jet lag. While the sun may be coming up, their circadian clocks are telling them that it feels like a different time of day, so they crow in response to the light, but with reluctance and confusion, much in the same way you sleepily get up on vacation when the Louvre opens, even though it feels like 5PM to you.

“But Austin,” you tell me, “aren’t you anthropomorphizing?” While I admit roosters may not empathize with trans-Atlantic travel, we know that chickens are dependent on daylight to calibrate their biological rhythms because we do it all the time. We increase egg production by simulating summer lighting year round, and alter feed intake in broilers by changing their daylight cycle. We also use this trick to bring mares into heat.

The loss of rhythm observed in 24 hour dim light is likely to become more and more sporadic, and even more so if the roosters were housed singly (as there is some group consensus due to competitive crowing). I would propose that if you could keep the roosters on a light cycle that progressively moved forward an hour a day until dawn was at 2pm, the roosters would crow with the same strict rhythm independent of the actual sun. If the authors of the study choose to pursue this hypothesis, an easy test would be to simply progress their artificial sun’s rise and fall over time.

Alternatively, we could fly several roosters with us to Paris, and see if they wake us up before the Louvre opens.

ResearchBlogging.org

Shimmura, T., & Yoshimura, T. (2013). Circadian clock determines the timing of rooster crowing Current Biology, 23 (6) DOI: 10.1016/j.cub.2013.02.015

“Organizational silos,” and how they prevent effective zoonotic disease tracking

It appears that the agencies that we rely on to track disease outbreaks need to start tracking disease, not just their own jurisdiction.

An article in Sociology of Health and Illness piqued my interest this last week that reveals the amount of segregation different government agencies have when dealing with zoonotic disease. The understanding of the goals and connections between livestock, wildlife, and human health among these agencies are often apathetic at best, and antagonistic at worst.

The author of the article took it upon himself to interview several government agencies with different species and regional jurisdictions, and was able to reveal what he calls “organizational silos” that develop when the values and cultures of these different agencies prevent them from working with outside groups. When attempting to monitor emerging infectious disease (EID), identification of cross-species movement is critical to predicting and preventing pandemics. Unfortunately, while they may be able to acknowledge the geographical movement of EID’s, many organizations are blinded by their specific oversight of humans or animals.

Copied from the article: Diagram showing the crossover between domestic animals, wildlife, and human EID. Important emergence factors for each circle are listed on the outside.

There are many telling comments contained in his interviews, and I encourage you to read the article to get the whole scope of the problem, but I’ve chosen to list a few of my favorites here:

From the Director of Animal Health Division at a state Department of Agriculture:

“‘We got a positive [flu result] on one of our routine surveillance tests’ of a poultry farm, Spencer complained, and ‘we were required to contact the USDA right away because of the pandemic Asian strain’. Spencer added, ‘It seems a little silly because there was no clinical illness on the property, and the strain came back something pretty common…’ In Spencer’s eyes, it was ‘hard to justify’ reporting the flu strain to the USDA… These days, Spencer said he passes on information about disease events to the state DOH and leaves it to them to tell local health boards. ‘If somebody screws up’, he shrugged, ‘at least we can blame the [Department of Health]’.”

Not an uncommon perspective for many organizations, or even coworkers! Let’s hear from another director at the USDA Animal and Plant Health Inspection Service (APHIS):

 “Clinton argued that the ‘single biggest threat for disease’ comes from ‘wildlife intermingling with domestic livestock’. He told me, ‘You can’t control the birds’ and he rightly pointed out that ducks are flu incubators. If the bird flu – which Clinton called the top priority of his agency – becomes pandemic in humans, he told me, it will come from waterfowl.”

Interesting, I might argue that we have much more interaction with domestic fowl (can’t remember the last time I handled a wild duck) and that they therefore were the point of spreading, but let’s see what others had to say about this viewpoint.

“Nina Marano, a zoonotic disease expert at the CDC, told me that ‘most of the outbreaks have occurred through interaction with domestic poultry’. Another example: though poultry farmers singled out wild birds called cattle egrets as the source of a 2004 flu outbreak in California, the egrets tested negative – it turned out that contaminated egg containers circulating between farms were the culprit (McNeil 2004).”

Finally, one last example of how a zoonotic disease often isn’t treated as such by human health agencies. From a Director of the Infectious Disease Bureau of a city Public Health Commission:

“When I asked Sanders to describe a zoonose that she responded to, she mentioned a recent outbreak of salmonella…and she believed that the pathogen came from two live poultry markets in Chinatown. What I found telling was that, in Sanders’ lengthy discussion of this outbreak, she did not mention any communication with veterinary medicine agencies.While the Disease Bureau’s response to salmonella followed protocol, it did not turn to the Department of Agriculture, the USDA, or any other agencies involved in animal health for help or information. Nor did it share information with them.”

Clearly here the city health board considered this a food safety issue, but payed no attention to the implications of getting meat from an approved source (a domain which definitely belongs to the USDA or county health department), or the fact that other agriculture agencies may be interested in a salmonella outbreak. There are many other telling quotes within these interviews, and I again encourage you to check out the article.

The author of the study concludes that the only examples we get of harmonious collaboration are for those diseases which are in the public eye such as rabies and influenza (H5N1 and H1N1), though we still have lines drawn even when the public is asking for action (“‘we have enough H1N1 to worry about without worrying about turkeys’. He
concluded that turkey infection is ‘a Department of Agriculture issue’”). The most shining example of the failure to communicate by these institutions in the article was the outbreak of Bird Flu in the US.

The first human cases of H5N1 in the US were wrongly diagnosed with St. Louis encephalitis, resulting in the deaths of 3 patients. A veterinary pathologist at the Bronx zoo observed neurological symptoms in some of the zoo’s birds and suspected a link, however encephalitis would not have killed her birds. Both the CDC and local DOH would not accept new information from her, instead keeping the encephalitis diagnosis. She then sent specimens to a friend at an Army Medical Research Institute of Infectious Diseases, who revealed the etiology of the disease and I’m sure had a hilarious conversation with the CDC and DOH (could you please explain to us why this veterinarian is doing your job casually on the side, and doing it better?). By the time the CDC received/accepted this information, H5N1 was endemic in the area.

Nothing against the CDC, it’s a fantastic organization, but this highlights the closed lines of communication that exist between human and animal agencies the author discusses. In order to prevent the next EID crisis, rigorous epidemiology is critical. Refusing to acknowledge the importance of cross-species movement to the virulence and emergence of a disease that falls under your agency does not only prevent you from identifying the next source of infection, but leaves you with nothing but reactive measures catered to a epidemic that you refuse to fully appreciate.

ResearchBlogging.org

Jerolmack, C. (2012). Who’s worried about turkeys? How ‘organisational silos’ impede zoonotic disease surveillance Sociology of Health & Illness DOI: 10.1111/j.1467-9566.2012.01501.x

Do organic animal operations encourage management decisions that negatively impact animal welfare? Part 3

Here’s the final portion of my paper: Do organic animal operations encourage management decisions that negatively impact animal welfare?

If you’ve missed the other posts, you can check out part 1, part 2,  or read the entire paper here.

 

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Conflict Between the Organic Approach and Welfare Ideals
Despite measures taken to promote prevention, a certain amount of disease is permissible in a healthy ecosystem and the restrictions placed on organic producers by both their certification requirements and ethos can create dilemma’s that could potentially harm animals. Several classic examples of species specific situations have been examined where the animal welfare approach taken by organic producers can be considered detrimental to the animal.

It should be noted that while there is evidence that there is a reluctance to use prohibited medications and chemicals to treat disease on organic farms (Vaarst and Bennedsgaard, 2001), both the Code of Federal Regulations (CFR) and IFOAM standards explicitly state that organic livestock producers must not withhold medical treatment from a sick animal in an effort to preserve that animals organic status (IFOAM, 2005; National Archives and Records Administration, 2012a; Riddle, 2008, 2012).

Dairy
Management of mastitis in organic dairies is a commonly discussed example of when health of the individual and a reluctance to accept the financial loss associated with antibiotic use can potentially harm the animal. Herd health, in general, has not been shown to be significantly different between organic and conventional dairy herds, and some data suggests that the incidence of disease may actually be lower in organic herds, though the reasons for this are unknown (Lund and Algers, 2003; Lund, 2006). Interestingly, the ban on antibiotics for clinical use is more of a concern within U.S. boarders, as the majority of certification standards in the European Union allow antibiotic use to treat clinical disease without jeopardizing the organic status of the animal (Ruegg, 2009). However, the strict FDA guidelines for organic milk production not only prohibit the use of antibiotics in organic livestock, but do not allow the use of any compounds with an antimicrobial effect that are not approved by the FDA for organic production (National Archives and Records Administration, 2012a). Currently, there are zero antimicrobials approved for use in organic animals (Ruegg, 2009). This leaves organic dairy producers extremely limited in their options for treatment when faced with a cow that has mastitis. With few options available, Zwald et al. (2004) were able to find that farmers who switched to organic production began to seek information on treatments from other organic farmers as opposed to veterinarians. This trend is not seen in countries where antibiotic options are available to organic dairy farmers (Hamilton et al., 2006).

So what options are available to organic dairy producers in the U.S.? Once again, prevention is key, but research has shown that rates of mastitis are similar between organic and conventional dairy operations (Lund and Algers, 2003; Lund, 2006). This indicates that treatment must be part of a management plan, even if the organic ethos prevents any attempts to interfere with natural processes through antimicrobial intervention. Certain drugs are available for use on the CFR’s approved substances list with increased withdrawal times to maintain the high standards expected in organic milk production (Riddle, 2008; National Archives and Records Administration, 2012a). These drugs include certain anti-inflammatory drugs that would be useful in treating fever and inflammation associated with mastitis. Beyond pharmaceuticals, therapeutic care including frequent milking is a recognized way to discourage bacterial growth within the affected quarters. Combined with approved anti-inflammatory drugs, frequent milking and supportive care constitutes a common mastitis treatment on organic dairies in the United States (Ruegg, 2009).

Many organic farmers will also attempt to utilize complementary and alternative medicines; however, almost all of the products available have not been evaluated in peer reviewed studies for efficacy. Immunoboost, a USDA licensed immune stimulant sold in the U.S., has been evaluated but has not shown to have any significant effect on the treatment of mastitis (Ruegg, 2009). Other various remedies including peppermint, aloe, and garlic have been utilized by organic farmers as intramammary treatments, however the efficacy of these options is doubted, and their use is prohibited by the FDA (National Archives and Records Administration, 2012a). It appears that without recovery using simple supportive care, any medical intervention necessary to prevent unnecessary pain or distress for non-responsive mastitis cases will result in the loss of a producing animal for that organic operation. This creates a potential welfare risk, as the USDA organic requirements do not specify a point when prohibited treatments must be used, and the decision to discontinue organic treatment resides solely with the farmer.

Poultry
Poultry producers face a distinctive management change when converting to organic as free choice medicated feeds containing antibiotics are commonly used to manage disease and promote growth (Love et al., 2010). Organic poultry is also currently under increased pressure from consumers (Love et al., 2012) to provide a safe and antibiotic free product, which could indicate an increased reluctance to treat conditions using pharmaceuticals. Following the prevention management strategy, organic poultry producers may use a variety of feed supplements including probiotics, prebiotics, organic acids, and plant extracts that have had minimal and sometimes contradictory efficacy reviews (Griggs and Jacob, 2005). Once again, treatment needs to be a key part of the management strategy of the organic producer, and the increased public scrutiny over medication use in poultry has the potential to encourage famers to withhold medication as has been shown in other species (Lund, 2006).

One of the most contested animal welfare debates surrounding organic poultry is regarding the space required by the USDA regulations to remain organic (Kijlstra and Eijck, 2006). While the law only requires year-round access to the outdoors, shade, shelter, exercise areas, fresh air, clean water for drinking, and direct sunlight (appropriate for the species, age, and climate) (National Archives and Records Administration, 2012a); organic farmers have adopted the term “free-range”, which unfortunately like the word “natural,” has no legal meaning. Nonetheless, open access to runs follows the third of Frasier et al.’s welfare ideals in allowing chickens to exhibit natural behaviors and thus have better welfare. The trade-off, however, is that while we have defined the major focus of disease management in organic operations as prevention based, free ranging chickens are more susceptible to predation, outbreaks of cannibalism, parasite exposure, coccidiosis and ascarid infections, and interactions with wild fowl that transmit dangerous diseases such as avian influenza (Verhoog et al., 2004; Kijlstra and Eijck, 2006; Lund, 2006). In order to keep with organic standards, all of these animals must continue to have access to the outdoors, and prohibited pharmaceuticals cannot be fed to treat outbreaks of disease or treat the higher rate of parasites that are found on organic operations (Lund, 2003). Clearly, should there be an outbreak of disease or cannibalism, an ethical dilemma is created between the first two ideals concerning the physical and mental needs of the animal, and the third to maintain natural conditions.

The various dilemmas discussed indicate that organic producers face additional pressure, both financially and in public relations, to avoid the use of treatments that would compromise the organic status of that animal. However, prioritizing animal welfare to include aspects beyond the scope of the clinical health of individual animals can potentially change the way welfare is perceived by conventional farmers and the general public. If an ecocentric rather than an individualistic perspective is considered, and positive experiences can be provided for the animal by indulging its natural behaviors and ecological niche, perhaps some stress events like occasional infections are an acceptable trade-off. Given that a higher incidence of disease has not been found, and that organic producers are required by law not to restrict care to maintain an organic status, it can be determined that organic livestock production does not encourage decisions that negatively impact animal welfare. However, it is recommended U.S. should adopt the EU policy of allowing antibiotics to be used in clinical cases without removing the organic status of that animal. With adequately increased withdrawal times in place to reflect the strict requirements that define organic products and enough consumer education, the organic market should recognize and accept the benefits of this policy change. Livestock would benefit by receiving more aggressive medical intervention as financial pressure not to treat animals could be alleviated as it has been in the EU (Ruegg, 2009), and having prescription antibiotics available as a treatment option could encourage more contact with veterinarians instead of neighbors to discuss animal health. Additional research is needed to support this position that could come from data determining if financial and public pressure are enough to encourage farmers to withhold treatments. In that case, additional actions such as stricter enforcement of the law may be necessary to promote a higher standard of care for organic animals.

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What do you think? Does my assessment compare with your personal observations or more recent research? Do you think there are conditions in which antibiotics should be permitted while maintaining the organic standard?

Do organic animal operations encourage management decisions that negatively impact animal welfare? Part 2

Here’s the second portion of my paper: Do organic animal operations encourage management decisions that negatively impact animal welfare?

You can find part 1 here, or read the entire paper here.

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Welfare from an Ecocentric Perspective
Animal welfare has always been and remains to be an important goal in organic operations (Riddle, 2005; IFOAM, 2005); however, organic producers are still questioned on the welfare status of their animals because of their organic certification. Among the many definitions intended to quantify animal welfare, Frasier et al. (1997, p.187) provide three basic animal welfare ideals:

1. The animal should feel well, corresponding to the concepts of experience, feeling, interest, and preference.
2. The animal should function well, corresponding to the concepts of need and clinical health.
3. The animal should lead a natural life through the development and exercise of its natural adaptations, corresponding to the concept of the “innate nature” of the animal.

In general, livestock in conventional settings have their welfare measured using the first two ideals, with the most emphasis placed on the second. Producers are first and foremost concerned with the prevention of disease that could hurt production or cause unnecessary pain; humane slaughter laws are designed to prevent excess excitement and discomfort (National Archives and Records Administration, 2012b), and welfare audits for slaughter facilities are designed to reduce animal stress prior to slaughter (Grandin and Johnson, 2006). Using these criteria, it becomes clear how viewing welfare through the first two of Frasier’s ideals might suggest organically raised animals could have poorer welfare. It has been shown that organic farms have a higher rate of parasite-related disease (Lund and Algers, 2003), and the use of veterinary drugs is strongly suggested to be a last resort after alternative methods have been exhausted (IFOAM, 2005). There is also a financial incentive, as once antibiotics have been given to an animal, that animal cannot return to organic production (Riddle, 2008; National Archives and Records Administration, 2012a).

Through the naturalistic perspective however, welfare for organic producers can depend much less on the first two ideals, and more weight is placed on the third. This viewpoint changes the significance of the risks involved in many organic practices, such as free range housing, as both organic producers and consumers emphasize the third ideal as a priority (Alroe et al., 2001; Lund, 2006). Additionally, the ecocentric perspective further lowers the emphasis on the first two, as disease and parasites are both considered healthy parts of a larger ecosystem, and the health of the ecosystem is crucial to the health of the herd and the sustainability of the farm. This idea of looking past the individual is what causes dispute when quantifying animal welfare on the organic farm. Most producers, veterinarians, USDA inspectors, and animal owners evaluate animal welfare at the level of the individual, whereas the ecocentric organic producers are more likely to evaluate welfare at the level of the flock/herd, within the herd’s role in the overall ecosystem. At this level, a few animals in poor health are acceptable in a natural ecosystem where small amounts of disease are permissible. The ecocentric view disallows an attempt to alter a healthy system determined by nature by eradicating this small population.

Because animal welfare may be determined using more qualitative criteria in an organic operation, how do organic producers react to poor welfare or illnesses of individual animals? Organic producers hold the health of their animals high in their priorities (IFOAM, 2005; Riddle 2005), so they must be able to maintain a standard of herd health not only for the benefit of their animals, but to keep production high. As part of the naturalness or ecocentric ethos, organic producers believe that farmers should not try to take control of the environment, as conventional techniques do, but work hand in hand with nature. Thus, any method used to completely eradicate disease through the use of chemicals or medications does not promote a sustainable ecosystem, as it reveals an attempt to control the environment rather than work to bring the ecosystem back into balance (Verhoog et al., 2003). Therefore, prevention becomes key, and the U.S. organic requirements mandate preventative practices that emphasize working with nature such as selection of species and type of livestock that are appropriate to the site and resistant to prevalent disease, provision of a sufficient organic feed ration, and the use of appropriate housing, pasture management, and sanitation protocol to minimize the occurrence of pathogens (Riddle, 2008).

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Read the final section of the paper here: Do organic animal operations encourage management decisions that negatively impact animal welfare? Part 3.

Do organic animal operations encourage management decisions that negatively impact animal welfare? Part 1

For my senior ethics class, I chose to write about an issue everyone has an opinion on, from granola folks at the co-op telling me to watch Food Inc. to farmers complaining about the outbreak of upper respiratory disease from those untreated organic herds sneezing over the fence. I actually ended up changing my own views quite a bit following the extensive research I did, and I really enjoyed writing the paper. I wanted to evaluate the claims often made to me by professors in my land grant school (Oregon State) about the misleading advertising and hidden evils of organic production, and I wanted to see if there was anything to back up the fanaticism and devotion sometimes projected by organic devotees. This paper is NOT an exhaustive review of the literature, and I am not qualified to make any official judgement, and is simply meant to be a personal commentary from a recent graduate.

So rather than sit here blathering, the first portion is below, and you can read the full paper here.

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Few agricultural debates come close to generating the same passionate and heated responses that organic farming seems to elicit. The discussion surpasses the interests of producers with conflicting ideologies to be hotly debated by assertive consumers as well; people who highlight the paradox created by their interest in the safe and responsible production of their food, while avoiding all involvement in its creation. The originally proposed Organic Foods Production Act of 1990 received nearly 300,000 comments on the proposed requirements, more than any other piece of legislation in history (Vos, 2000). Clearly this indicated that the role organic farming played in food production was extremely important to U.S. citizens then, and continues to be a relevant topic as organic operations have grown by 40-50% every five years since 1992 (USDA, 2010).

The general public also has a strong interest in the way animals are managed, especially when management techniques play a role in the health or well-being of the animals prior to their use for meat, milk, or eggs. Humane management is often brought up when discussing the merits or flaws of organic operations, and is extremely important to producers due to the important role animal welfare plays when consumers make purchasing decisions. Prickett et al. (2010) found through the use of a telephone survey that 49% of consumers consider the well-being of farm animals when purchasing meat, and 83% of consumers disagree that lower prices are more important than the well-being of the animals used. These numbers become critical when organic producers need to justify the increased cost of their products and conventional producers are forced to avoid the alternate impression that their animals are treated poorly.
Marketing pressure placed on both groups leads to a vicious back and forth of both valid questions and vague accusations, among which is the suggestion that organic farms can act as reservoirs of disease (Kijlstra and Eijck, 2006). One mechanism for this accusation could be the avoidance of chemical or synthetic intervention for pest control and treatment of disease. This paper seeks to evaluate organic farming ideologies and legal constraints that create ethical dilemmas surrounding animal welfare, and determine whether organic management encourages decisions that are detrimental to the animals involved.

Animal Welfare and the Organic Movement
Early organic movements were created with the goal that a more sustainable and environmentally friendly farming system could be created that would benefit not only farmers and consumers of organic products, but also the animals within this system (Lund, 2006). These ideals have persevered and are a common talking point in promotional materials that market organically raised animals as drug and chemical free, and much closer to a “natural” condition (Riddle, 2005). This concept of “natural” is commonly used to differentiate organically produced animal products from conventional ones.

Utilizing the word “natural” creates an issue of perception; while the public widely accepts “natural” as a product descriptor, the word itself has no published legal definition when used in food advertising or packaging in the U.S. However, consumers have been shown to associate descriptions of “naturalness” not only with animal welfare but sustainability and care for the environment (Verhoog et al., 2003). While this may imply a scheme to sway consumer loyalty, the word is widely accepted by organic producers as an accurate descriptor to differentiate organic methods from conventional. While “natural” can have broad definitions like including the entire universe or everything untouched by man (thus either removing agriculture or providing no distinctions in practice), Verhoog et al. (2004) were able to show that organic producers feel organic can be classified as more natural than conventional agriculture as its aim is to be harmoniously integrated into nature. In this way nature is seen as a teacher or model for sustainable and humane agriculture. This ethos pushes organic farmers into an ecocentric approach when making management decisions. From this perspective, we begin to see how organic farmers may view welfare differently than conventional farmers or veterinarians.

Read the next section of the paper here: Do organic animal operations encourage management decisions that negatively impact animal welfare? Part 2.

 

ResearchBlogging.org
Vonne Lund, & Bo Algers (2003). Research on animal health and welfare in organic farming—a literature review Livestock Production Science, 80 (1-2), 55-68 : 10.1016/S0301-6226(02)00321-4

Risk factors for companion animal (cats, dogs) vaccine reactions

I’m apparently still on this immunology kick, because I seem to be finding it everywhere. Heck, I recently learned that we’ve cured the allergic response to peanuts and eggs in lab mice. Check out the link, the author is hilarious and the material is interesting.

These two articles offer a great look at the overall prevalence and risk factors associated with vaccine-associated adverse events. The components within the vaccine that cause these events are the antigen itself, adjuvants, preservatives, stabilizers, and residues from the tissue culture used to grow the vaccine (Moore, 2005). Vaccine reactions are similar to any acute allergic reaction, and can present with a variety of mild to severe symptoms. The mild being lethargy, anorexia, fever, edema (generalized or local to the injection site), pruitis, uticaria (hives or wheals), and pain at the injection site; the severe being vomiting, dyspnea (labored or shortness of breath), and anaphylaxis. There’s a lot of information about when certain symptoms tended to occur at intervals after the vaccines were given, but any reaction that isn’t within the first 3 days is pretty much never going to be life threatening. If anaphylaxis is going to occur, it’s going to be immediately following vaccination.

The really useful information was the breakdown of risk factors that can be used for client communication. I’ve decided to discuss them here, broken down into cat and dog categories.

Image from meow-cats.com

First, let’s start with cats. I almost like these numbers more because you don’t have to take into account bias based on animal or breed size, as most cats fall into the <20 lbs category. Nonetheless you still have to remember that a 4 pound kitten does way only a fraction of that 5 year old chubby (BCS >5 on a 9 point scale) longhair it will grow to be.

So the first two risk factors require a little bit of thinking in context to explain the numbers. It seems that cats weighing 2-4 Kg (4.4-8.8 lbs) and approximately one year of age are most at risk compared to other weights and ages. The high numbers for these groups can be explained by the number of first encounter events that occur. If you’re recording vaccine reactions, you will record less in older age groups and higher weights (low weight under 10 lbs is going to be suggestive of a young age rather than a smaller cat), because if an adverse event occurred at a young age, either the animal is no longer vaccinated or steps are taken to reduce its risk (medication, strict scheduling, vaccine selection). That being said, just because the numbers are higher by circumstance, this information is very relevant in a clinical setting. Knowing the epidemiology of these events can help technicians at clinics determine when the discussion of vaccine reactions is “routine” or “protocol”, or when it really needs to be a time to educate the client. Vaccine reactions may need to be just a bullet point when Schrodinger is there for his 4th rabies booster and a discussion when he’s receiving his kitten series.

Sex and neuter status have a large impact on reaction risk as well. Intact males actually have a lower risk of adverse events than neutered males and spayed and intact females. Apparently, estrogen has an immune boosting effect, while testosterone has an immune suppressing effect. This benefits intact males when it comes to all allergic reactions (and possibly auto-immune disorders).

Here’s the big one, and the one clinics have the most control over. With each additional vaccine given in a single visit, the risk of an adverse event increases by 28% in cats. That’s huge. Any cases of severe anaphylaxis or death recorded in the study were preceded by the animals receiving 3 or more vaccines in one visit. So clearly the biggest thing any clinic can do to prevent adverse events (or at least severe ones) is to adopt a vaccination schedule that prevents multiple vaccinations from occurring within the same visit. This can be difficult as clients will not want to end up paying for multiple exams throughout the year, but with boosters outside of rabies, exams shouldn’t be necessary unless an annual or other scheduled exam is due. As far as specific vaccines being more prone to adverse events, the only suggestive evidence was when both FVRCP and FeLV were given within the same visit. This is explained by both having two concurrent vaccinations given, and also the theory that vaccines containing multiple antigens or covering multiple serovars (multivalent) are more likely to illicit reactions. Interestingly, while clients are often scared by the potential for vaccine caused neoplasia from the rabies vaccine, it was among the lowest reaction rates observed with the administration of a single vaccine.

Image from peteducation.com

Dogs had much more biased data within the age and breed groups because there is an obvious relationship between body mass and the potential for reaction. When looking at the dog population, a chihuahua can be as little as 6% of the weight of a bullmastiff, yet they receive the same 1ml dose of vaccine. This means that an 8 lb Chihuahua is going to receive proportionally 15 times more vaccine than a 120 lb bullmastiff. Not surprisingly, this causes a bit of inflation in the number of reactions in groups that are smaller in size, such as toy breeds and puppies. The highest risk group in size was 0-10Kg (0-22lbs) and the highest risk age was approximately 2 years of age (with higher rates for <2 than the rates of >2).

Just like I mentioned before when talking about cats, the greatest risk factor for reactions in dogs was the amount of vaccines given in one visit. The difference though, is how the large weight distribution in dogs makes this even more important. Small dogs (<10Kg) are similar to cats in that their risk increases by 24% with every additional vaccine administered that visit, while large  dogs (10-45Kg) increase their risk by 12 percent. All 3 dogs in the study that suffered fatal reactions received 4 or more vaccines at once.

Breed dispositions were difficult to pinpoint, as the suspected breeds are all small breeds which suffer a higher rate of reaction already due to their size. There is suspicion that dachshunds may be predisposed to allergic reactions in general, but so far the evidence is inconclusive concerning vaccines. Only the Lyme vaccine appeared to carry a higher risk than any other, showing again that, with the exception of neoplasia concerns, rabies does not carry with it any additional risk. Spayed and neutered animals, as in cats, are more susceptible to reactions; however the difference between intact and spayed females is much larger in dogs than in cats (where they are nearly identical). Dogs do seem to display an interesting trend where vaccine reactions are more likely to occur on the 3rd booster in a series, likely catching clinicians and clients off guard as they have received the first two without incident. This just states again that the puppy and kitten periods (and new patients) are of much more relevance when discussing vaccine reactions with clients.

The articles are both great, and contain an excellent statistical analysis of millions of animals. They provide a great overall picture of the epidemiology of vaccine-associated adverse events, and are definitely worth a read for both veterinary doctors and staff. Knowing a couple of the more important statistics can reassure the client and lend credibility to technicians that are responsible for discussing these issues.

ResearchBlogging.orgMoore, G., DeSantis-Kerr, A., Guptill, L., Glickman, N., Lewis, H., & Glickman, L. (2007). Adverse events after vaccine administration in cats: 2,560 cases (2002–2005) Journal of the American Veterinary Medical Association, 231 (1), 94-100 DOI: 10.2460/javma.231.1.94

Moore GE, Guptill LF, Ward MP, Glickman NW, Faunt KK, Lewis HB, & Glickman LT (2005). Adverse events diagnosed within three days of vaccine administration in dogs. Journal of the American Veterinary Medical Association, 227 (7), 1102-8 PMID: 16220670