African pig seasonal febrile diseases is poisonous, what send ill force according to its is different, can divide to cause disease high gender, medium the sex that cause disease and the low sex that cause disease 3 kinds. Send ill sex poisonous individual plant high to be able to cause severe acute disease, the mortality of poisonous individual plant that noxiousness waits for in the mortality; that achieves 90-100% in day of the 4-15 after infection is in the mortality of poisonous individual plant of the low sex that cause disease is in 30-70%; 10-30% .
After low level is affected in, survive the pig that come down takes a pig whether for a long time only and outward bound discharges poison, this is the focus of long-term argument. Germany the academy diagnoses Fulidelixi Lefule the researcher of virus place gave out oneself experimental conclusion.
One
Experimental design
In the experiment, researcher chose 36 virus that be not acute communicable diseases to detect the 5-6 month pig that check-up of Wen Kang of electronegative, blame measures negative, among them 30 serve as the pig that attack poison, the Netherlands that waits for noxiousness in Dutch with depart ' the way that 86 poisonous individual plant develop clear droplet bazoo through virus undertakes vaccinal infection, call C pig. Random cent is C pig 3 groups, every groups 10, close in a big hurdle that piggery becomes independent 3 times respectively.
Odd 6 not vaccinal virus, use at column is the same as to raise with its in later period of C pig infection, detect the infection ability that affects later period C pig, call S pig.
After infection, c pig detects everyday rectum temperature observes clinical phenomenon. If two days of above reach temperature 40 degrees, think to have a fever truly. Clinical observation symptom includes: Lively degree, be able to bear or endure suffer degree, ventilatory frequency, gait, skin, eye, cheek and collect appetite to wait, build grading system.
The pig after be being affected for judge the degree with poison of virus blood disease, platoon and respondent immunity, in infection the 3rd, 7, 10, 14, 20, 29, 42, 48, 63 have laboratory test with blood of vein of the 91 antrum before the day is draw-out.
Be the same as for a short while, to detect infection pig discharges poisonous circumstance only, mop of the autograph that use cotton child collect include sample of excrement and urine, saliva and sample of buccal pharynx ministry inside mop increment is tasted, use as QPCR detects. Arrive 126 days from 105 days, mop increment is tasted collect every week.
After 99 days, 19 C of survival pig and 6 S pigs are mixed raise, every groups put 2 S pig, press originally experimental design is collected of all kinds detect sample. After 164/165 day, the C that all surviving pig and S pig is anatomized collect constituent specimen to detect, include: Tonsil, salivary gland, milt, lung and mandible lymph node, and the much place lymph node such as inguinal, liver, kidney, intestines and stomach, lung.
All mop increment is tasted, of the virus in haemal sample and constituent specimen should use PCR of real time ration to detect, antibody detects with ELISA. To detect blood is mixed the virus that there is active in the organization, experiment of adsorption of applied blood cell detects.
2
Experimental result
1
Clinical symptom
The Netherlands of medium noxiousness ' the C after 86 poisonous individual plant are affected pig shows a variety of different and clinical symptoms, include acute deadly, defer is deadly, chronic disease, and restore finally to wait.
Most pig is in only infection 4-6 day, appear have a fever symptom. Go up alone in the pig that acute dies, clinical symptom expression is dejected, conjunctivitis, do not collect feed, constipation, skin is erubescent, special have a fever in ear and eye area; 41.8 ℃ , a few pigs are in high fever appears after 5 days symptom of central nervous obstacle. Acute symptom lasts on average 8-10 day. The pig that this phase dies, anatomize discovery many viscera bleed: Strut of week lymph node is mixed outside haemorrhage, nephritic haemorrhage dot and lung oedema.
2
Virus detects
After 30 all C pig is dripping to catch period of time nasally, exsanguinate does QPCR to detect check gives masculine gender, detect for the first time the time that gives masculine gender is in after infection between 3-21 day. Be in the 10th with 14 days, content of the virus in blood is the biggest. In infection the 42nd day, QPCR of first time of 6 C pig detects the result shows negative, the 48th day 7, the 63rd day of 10 head results are negative. Arrived the 91st day, although the C of 52% pig remains the same electropositive, but virus carried a quantity to reduce (Cq 28-30) .
HAT of sample of blood of 30 C that are the same as time pig detects (HAT detects electropositive specification ASFV has infection active) discovery, serum HAT detects result and haemal PCR result are consistent, most HAT detects positive result appears in 14 days of infection. Interesting is, HAT the first negative result appears in 29 days, occurrence HAT of the C that survives in great quantities subsequently pig is electronegative, the C that went to all surviving the 63rd day pig detects electronegative. This may show pig of surviving the infection that be not acute communicable diseases loses infection ability to want to antedate nucleic acid detects negative result appears.
Cotton signs mop child sampling detects poisonous circumstance of the C that shows infection ASFV as a result pork chop. Increment of oral cavity mop tastes QPCR to detect in infection the 3rd day appears positive result (bicephalous pig) . Be in the 7th with 10 days, the increment of oral cavity mop of great majority tastes occurrence positive (Cq is between 30-41) . Begin from the 14th day, electropositive mop increment tastes an amount to begin to decrease, arrive the 21st with 29 days, only a sample presents masculine gender, arrived the 42nd day, increment of all oral cavity mop are tasted present negative. Salivary sample and oral cavity mop child the result is consistent, in height of result of 7-10 day occurrence positive, begin to decrease in 14 days. Different is, salivary sample virus carries quantity more, duration is longer. The virus content in sample of excrement and urine is lower, final electropositive shape appears in the 29th day.
ELISA detects circumstance of infection pig antibody. The first batch of doubtful results (5) with positive result (13) appear the 13rd day after infection, subsequently amount of antibody positive pig and antibody block break rate stability to increase (increase) . Arrived the 29th day, antibody of all C pig indicates masculine gender (block is broken rate in 74-98%) , arrived the 63rd day, block of all C pig is broken rate achieve 99-100% . Surviving C pig still behaves masculine gender till experimental end, but the antibody that the antibody of generation is particularity of ASFV P73 albumen, but the antibody that cannot produce Youzhonghezun to use.
6 S pig begins to come from the experiment end, did not behave blame acute communicable diseases to affect clinical symptom, QPCR detects, HAT detects and ELISA detects the result all shows negative, make clear in the 99th day, c pig survives to mix after S pig and infection blame acute communicable diseases raise, c pig already did not have infection capacity.
On put together, the Netherlands of medium noxiousness ' the pig after 86 poisonous individual plant are affected appears already inside 4-6 day only clinical symptom, and serious degree each different, include acute deadly, defer is deadly, chronic disease, and restore finally to wait. In infection a few days (the earliest 3 days) hind appear virus blood disease, can detect through the method such as experiment of PCR, HAT, begin occurrence platoon poison at the same time, can detect in the 3rd day of oral cavity and saliva virus, mucky at one's convenience is a bit late;ASFV antibody (P73 particularity antibody) appear later. Survive however the infection pig that come down can not take poison for a long time only, however the elapse as time, virus carries a quantity to be reduced gradually, keep clear of completely finally. Result of HAT experiment negative most appear first, subsequently QPCR result also will turn for negative, healthy pig is mixed with the surviving infection pig that affects 99 day hind only raise also won't appear infection. But survive the infection pig that come down can not arise to neutralize antibody effectively.
