anaplasmosis

[reccakerby]

Have had two dead newborn calves in the last week. The vet examined and took blood samples from the second calf. He said the calf had never breathed and the cause of death was anaplasmosis. However, none of my adult cows are showing any clinical signs of anaplasmosis. Is it possible for the calf to die of anaplasmosis when the cow shows no signs of infection with the disease? Would appreciate any help.

 

[TN Cattle Man]

First off... Welcome to the Boards. I am no vet and hopefully one of our vets here at CT will chime in on this post. I'm curious as to how your vet could come up with that diagnosis without any testing. With regards to Anaplasmosis, it is my understanding that it rarely shows any symptoms other then when it is too late and you find them dead. I hope you get an answer soon because if you do have Anaplasmosis going through your herd, you will need to jump on it quickly and treat all of you cows. Good luck and keep us informed.

 

[wbvs58]

Anaplasma marginale is a parasite of erythrocytes and will cause them to rupture. In Australia it is one of three blood parasites and is spread by the cattle tick. Cows in endemic areas will be immune to it and their offspring will have passive immunity from birth and then develop their own active immunity as they become exposed to ticks and there will be no losses in offspring.
Maybe in your situation the cow was unwell from the Anaplasma and from the anaemia and fever she aborted the calf. Was blood taken from the cow and stained and looked for Anaplasma? It does seem strange though.

Ken

 

[Bright Raven]

Have had two dead newborn calves in the last week. The vet examined and took blood samples from the second calf. He said the calf had never breathed and the cause of death was anaplasmosis. However, none of my adult cows are showing any clinical signs of anaplasmosis. Is it possible for the calf to die of anaplasmosis when the cow shows no signs of infection with the disease? Would appreciate any help.

To answer your question directly:

Is it possible for the calf to die of anaplasmosis when the cow shows no signs of infection with the disease?

Yes. There are different clinical conditions of infection. A cow can be infected and no show signs. Transmission from infected cow to fetus then can occur and the calf may be born dead.

 

[TCRanch]

First off... Welcome to the Boards. I am no vet and hopefully one of our vets here at CT will chime in on this post. I'm curious as to how your vet could come up with that diagnosis without any testing. With regards to Anaplasmosis, it is my understanding that it rarely shows any symptoms other then when it is too late and you find them dead. I hope you get an answer soon because if you do have Anaplasmosis going through your herd, you will need to jump on it quickly and treat all of you cows. Good luck and keep us informed.

That is often the case but they may suddenly exhibit aggressive behavior a few days prior to simply dropping dead. I've had one documented case of anaplamosis. Noticed the cow was on the fringe of the herd, drooling, just not acting right, her gums and vulva were almost white instead of a healthy pink. Vet diagnosed anaplasmosis and gave her a hefty dose of LA300 but I ended up selling her a couple months later, no longer showing any clinical signs other than just not acting right.

 

[TN Cattle Man]

First off... Welcome to the Boards. I am no vet and hopefully one of our vets here at CT will chime in on this post. I'm curious as to how your vet could come up with that diagnosis without any testing. With regards to Anaplasmosis, it is my understanding that it rarely shows any symptoms other then when it is too late and you find them dead. I hope you get an answer soon because if you do have Anaplasmosis going through your herd, you will need to jump on it quickly and treat all of you cows. Good luck and keep us informed.

That is often the case but they may suddenly exhibit aggressive behavior a few days prior to simply dropping dead. I've had one documented case of anaplamosis. Noticed the cow was on the fringe of the herd, drooling, just not acting right, her gums and vulva were almost white instead of a healthy pink. Vet diagnosed anaplasmosis and gave her a hefty dose of LA300 but I ended up selling her a couple months later, no longer showing any clinical signs other than just not acting right.

Totally agree with your statement! I was referring to the fact that not everyone checks their cows on a daily basis... a cow can appear healthy and fine, then three days later she will be dead! I have heard that most cows will show signs of being lethargic and can even become aggressive like you stated, but at that point it is only a matter of days unless aggressively treated.

 

[Lucky_P]

No. The unborn calf won't die of anaplasmosis... but may be aborted because the cow is anemic to the point of the calf dying in utero of hypoxia. IF anaplasmosis is the proper diagnosis... the cow will be clinically ill or dead within just a few days. If the cow is normal and continues to be... anaplasmosis was not the cause of abortion.

Several years back, I did full diagnostic workups on some near-term ET calves that were aborted. Found nothing in the way of infectious or toxic causes... but when the cows that aborted started dying 3 or 4 days later... we found the cause. Anaplasmosis.

Persistently-infected, non-clinically-affected anaplasmosis cows will have either been infected as young calves or survived (with our without treatment) a clinical case of anaplasmosis. These animals will not become clinically ill (and would not abort), but can serve as a source of infection for other animals in the herd, mainly via ticks feeding on them and then transmitting the Anaplasma organism to other cattle during subsequent feeding.

 

[pdfangus]

I have long maintained that a transmission device in addition to ticks is the big black, as the horse folks call them, B52 horse flies...they fly from animal to animal and are very aggressive blood feeders...
everyone tells me I am full of hockey....but these things are strong enough fliers to bring the disease from a distance away....
When I was an undergrad and we studied Anaplasmosis in diseases I recall being told that unless I went to Texas or points south I would never see it. Five years later I found dead cows and aborted calves one
September morning in central Virginia...vet diagnosed it pretty quickly and we treated 200 cows...never had a tick problem but those big black horse flies were brutal that year...
anaplasmosis is now a common disease in this part of Virginia

 

[Lucky_P]

pdf,
Moving cows around the country, we've also moved anaplasmosis (and other diseases) around with them. Sometimes you get more than you bargained for...
Unfortunately, the old Complement Fixation test we used to have was really poor... probably only detected maybe 15% of the infected animals - and those were probably the ones that were tested while in stages of clinical disease... it allowed a whole lot of persistently-infected but 'test-negative' animals to be moved across state lines. It was the 'state of the art' test at the time... but, in retrospect, it was really crappy. The cELISA test we now have is much more sensitive, and will detect those persistently-infected carrier animals, as well as animals in the incubation phase of the disease, as soon as 3 weeks or so after infection.

Most of the A.marginale strains in the USA are best transmitted by ticks... but some strains, like those we encounter in FL and CA are effectively vectored by biting flies.
When ticks feed on a 'carrier' animal, the parasite undergoes reproduction/amplification in the tick's intestinal and salivary gland epithelium - so, when that tick feeds on another cow, it can transmit large numbers of organisms, whereas biting flies can only transmit whatever number of parasites might happen to be on their mouthparts from taking a blood meal... and on a carrier animal, those numbers are so small that we can't even find them when we look at a stained blood smear.

Yes, horseflies can transmit it here (and where you are), but they're not particularly effective at it - they'd have to be feeding on a clinically ill animal with a high level of parasitemia, get brushed off and go pretty quickly to feed on a naive animal. Parasitemia in 'carrier' animals is so low that it's unlikely that they would transmit it. Normally, horseflies only feed every 3 days or so, so any parasites they might have on their mouthparts would die in between feedings.
Similarly, as a small trial conducted at KSU showed, WE can transmit anaplasmosis by using the same needles between animals. They had a cow with high parasitemia level, just about to become clinically ill... stuck a hypodermic needle in her, then stuck it in a naive cow; repeat, rinse... 6 of 10 naive cows became infected.

 

[pdfangus]

Thanks Lucky P

by the way we ran a close herd for thirty years....all new genetics came in a straw.

then one year we tested six calves to go to the bull test and all six came back positive.

I understand all that you wrote...

Except I have seen horse flies bite one animal and draw blood get brushed off and then go bite another one...

I try to use single needle use but then when the vet shows up she does not unless I remind her...

if a single needle without eyeball visible blood can transmit it that easily then I believe that a horse fly can transmit it just as easily...

 

[reccakerby]

Thanks to everyone for all the great information! The cow is still fine. No idea why the two calves were born dead at this point.