Dear Mary
I don't know if you remarked an email on promed on the 12 Nov on the disease of columnaris in fish caused Flavobacterium columnare. (Yes. Fish farming can make diseases more virulent, say researchers) The article describes how fish farming, an intensive farming business, enables more pathogenic flavobacteria to be selected and continue transmission as there is such a large number of susceptibles who are in contact with a diseased fish. Such bacteria would not be selected for in natural extensive fish living conditions in the sea or fresh water. This reminds me of highly pathogenic influenza which is selected for in intensive poultry systems.
The other danger of intensive farming is the accumulation of enormous numbers of organisms in comparison with extensive or more 'natural' farming conditions.
I am glad you have drawn attention to Q fever in the Netherlands. They have done too little about it too late- I ..have sent emails over the last year or so about Q fever drawing attention to the seriousness of the situation. It has developed into the current epidemic because of intensive goat farming systems where they do not go outside but live their whole lives in a shed in large numbers to provide a milking business.
They really have a problem. Q fever organisms may remain viable for decades in dust- there was an outbreak in Cardiff thought to be caused by taking down an old building where straw contaminated with spores had been stored or used in the fabric. Q fever occurs worldwide except in New Zealand! Those farms where infection has occurred in the Netherlands will be heavily contaminated with Q fever and a source for years to come. It is not only humans that are susceptible (one organism inhaled can cause infection) but also other domestic animals such as sheep, cattle, dogs and cats.
The organism is so infectious to work with in the laboratory that it is only cultured in very high containment facilities and all personnel working in such facilities are vaccinated because infection would seem to be unavoidable. Actually diagnosis of infection with Coxiella burnetii is quite difficult to do well and involves the preparation of reagents to detect immunogobulin types G, M and A to phase one and phase two Q fever antigens. It is best done in the UK by Dr Lloyd's containment level 4 laboratory at Porton Down where he prepares the reagents.
The diseases Q fever causes in humans, and I suspect also in other animals, are various. C burnetii is not only associated with abortions and pneumonia, but also with recurrent fever, hepatitis acute and chronic, cardiac disease- infection of the valves which can be fatal, and disease of the central nevous system, a meningoencaphalitis which can give rise to strokes and can also be fatal. Chronic disease is difficult to diagnose and treat and may need long term monitoring and follow up and may have limited responsiveness to long courses of tetracyclines or any other newer drugs that may have activity against Coxiella burnetii. Chronic infection with Q fever is usually way down on the list of diagnoses to be worked through methodically, and the specialist diagnostic antibody tests are essential- for instance in chronic hepatitis very high levels of IgA and IgM antibodies may occur not only to phase one antigens but also phase two. As response to therapy occurs in the liver so may the titres of antibody fall; follow-up may have to be indefinite.
The numbers of reported human cases in the Netherlands are bound to be an underestimate. Seroepidemiology on the human population and close monitoring of the situation in domestic animals is necessary to understand the extent of the Q fever outbreak. I expect the Netherlands are sensitive about doing this as it is a bad advertisement for tourism for example. Also I hope unpasteurised goat's milk and its products are banned. There should be active surveillance on all sheep and goat milking farms. Also on cattle dairy farms in the areas near known infected farms. I believe they should consider banning intensive goat farming for milk, likewise such sheep farming. On the farms where large outbreaks have occurred dismantling and burial of the buildings and their associated organic matter and dust should be considered, under continuous rain!
These sound like extreme measures but if vaccination of goats is the only measure taken the infection will continue to spread throughout the goat intensive dairying industry in the Netherlands, and to any such sheep intensive dairying industry. It may already be quite widespread in other domesticated animals where it may be sustained and continue to be a significant source of infection. It may be that small flocks of goats or sheep used for milking that are vaccinated, grazed outside, and kidded or lambed under guidance and monitoring of all premature abortions and miscarriages will not prove to be a risk of significant Q fever infection and source for other animals including humans.
There is a lot to be said for allowing animals natural living conditions.
best wishes
Ruth Watkins
UPDATE received from Dr Watkins an hour later...
I should point out that luckily the chronic infections and disease of the heart and liver, and recurrent fevers, are unusual in humans. This does have a bearing on the goats on the farms I would propose to close in their present form of 100s of goats living all their lives in one shed, one space. Goats are overwhelmingly likely to have acute infection with C burnetii that they clear. (I don't believe that a latent form of Q fever infection is known of)
The goats that have had an infection (could be screened for on serology) are the best immunised of all and there is no need to end their lives because of Q fever. The non-immune goats should be immunised some months before they are put to the billy. The spread of the organism in the environment arises primarily from placental products and infection of the placenta, with or without abortion, and this occurs in those goats infected during pregnancy or perhaps shortly before becoming pregnant. If the goats are grazing outside, not in holding pens and given hay, but properly outside, with grasses and scrub, they are unlikely to be exposed to infection at all, and even if brought in to kid in the final few weeks of pregnancy, will not therefore have infected placentas and amniotic fluid. That is probably why Q fever is not a big problem in Wales, because even though there are large flocks of ewes, 1000 or so, they are outside and either lamb outside or if inside are only brought in shortly before lambing.
Chlamydiale psittaci is a problem in sheep, perhaps because they infect each other by the respiratory route, but this also has the same proclivity as C burnetii for the placenta and infection can be spread by placental products. If ewe lambs are vaccinated at least 6 weeks before their first mating with the ram with a live Chlamydiale psittaci vaccine they are protected from infection during pregnancy and enzootic abortion (this is what I do with my small flock of sheep and every abortion is investigated, few so far, and where a cause found it has been an untypable campylobacter or an E coli infection). Toxoplasma gondii in sheep can also cause outbreaks of abortion with primary infection in pregnancy, but this is due to contamination of pasture with oocytes in faeces shed from young cats for about 3 weeks after the cats are first infected themselves. Again if this is a problem (I don't have young cats about) vaccine can be obtained most years, again a live vaccine given at least 6 weeks before tupping.
C psittaci can be associated with abortions in humans and T gondii also, and tragically the latter is also associated with foetal damage, most commonly to the retinae, also the damage can be severe to the brain and also fatal exactly in the same way as in lambs. The standard advice is that pregnant women should not go near the lambing shed or have anything to do with lambing ewes inside or out.
ends