HUIZHONG NEWS

The causes of diarrhea in farrowing units are numerous—Part: Porcine Deltacoronavirus

Since 2010, the widespread prevalence of a variant strain of PEDV in Chinese pig farms has led to vomiting and diarrhea among neonatal piglets in large-scale operations. The disease exhibits high morbidity and mortality rates, inflicting substantial economic losses on the swine industry. However, another member of the same genus—porcine deltacoronavirus (PDCoV)—can also produce similar clinical signs and exacerbate the economic impact caused by PEDV and TGEV. Therefore, in clinical practice, prevention and control of diarrheal diseases must be approached holistically: identify the core issues and reduce the infectious pressure posed by diarrheal pathogens. Since 2010, the widespread prevalence of a variant strain of PEDV in Chinese pig farms has led to vomiting and diarrhea among neonatal piglets in large-scale operations. The disease exhibits high morbidity and mortality rates, inflicting substantial economic losses on the swine industry. However, another member of the same genus—porcine deltacoronavirus (PDCoV)—can also produce similar clinical signs and exacerbate the economic impact caused by PEDV and TGEV. Therefore, in clinical practice, prevention and control of diarrheal diseases must be approached holistically: identify the core issues and reduce the infectious pressure posed by diarrheal pathogens! I. Overview of Porcine Deltacoronavirus Porcine deltacoronavirus (PDCoV), also known as type D coronavirus, belongs to the Coronaviridae family alongside PEDV and TGEV. Its genome is 25.4 kb in length—the smallest among known coronaviruses. The virus is primarily transmitted via the gastrointestinal tract but can also spread through the respiratory route. It is a recently identified pathogen that causes infection and illness across pigs of various ages. First reported in Hong Kong in 2012, outbreaks occurred in the United States and China in 2014. To date, PDCoV has spread to many countries and regions worldwide. Like other porcine enteric coronaviruses such as PEDV and TGEV, it features high morbidity and mortality rates, often resulting in large-scale diarrhea among piglets and significant economic losses. (Images below sourced from the internet) II. Hazards of Porcine Deltacoronavirus Following infection, PDCoV primarily manifests as depression, reduced appetite, a tendency to lie down, diarrhea, vomiting, and dehydration. Pigs at all growth stages may become infected, with nursing piglets and weaners being particularly susceptible. Diarrhea lasting 3–4 days can lead to dehydration and death, with mortality rates ranging from 30% to 40%, and sometimes reaching as high as 100%. (Images below sourced from the internet) Pathological Changes Post-infection necropsy findings resemble those seen with PEDV and TGEV, characterized mainly by thinning of the intestinal wall, copious pale yellow fluid in the intestinal lumen, and a stomach filled with undigested curd-like masses. Growing pigs, adults, and sows typically exhibit milder symptoms; these cases often resolve spontaneously with low mortality, though production performance and feed conversion efficiency are severely compromised. Additionally, studies have indicated that this disease can cause systemic infections, potentially linked to outbreaks of fatal conditions. (Images below sourced from the internet) Mixed Infections Recent research indicates a high incidence of mixed infections involving PDCoV, PEDV, and TGEV in large-scale pig farms, jointly triggering diarrhea and causing severe economic losses. (Images below sourced from the internet) III. Diagnosis and Control of Porcine Deltacoronavirus The clinical signs and pathological features of PDCoV closely resemble those of porcine epidemic diarrhea and transmissible gastroenteritis, making differential diagnosis challenging in the field. Laboratory testing—including virus isolation and identification, PCR, ELISA, and immunofluorescence—is required for accurate differentiation. Currently, there are no specific therapeutic agents or vaccines available for PDCoV. The most effective preventive strategies include: 1) strengthening biosecurity measures, adopting closed‑herd management practices, and implementing all‑in/all‑out systems; 2) ensuring routine vaccination against underlying diseases to enhance herd immunity; 3) prioritizing vaccination against porcine epidemic diarrhea and transmissible gastroenteritis, along with regular prophylactic medication to reduce secondary bacterial infections caused by E. coli, Clostridium, and other pathogens; additionally, microecological preparations can help improve gut health and immune function; 4) strictly enforcing quarantine protocols for introduced animals and intensifying monitoring of antigens and antibodies within the farm. IV. Summary In clinical settings, deltacoronavirus frequently co‑infects with transmissible gastroenteritis and porcine epidemic diarrhea, amplifying the severity of disease outcomes following PEDV and TGEV infections. Given the current lack of a vaccine for deltacoronavirus, it remains crucial to prioritize vaccination against PEDV and TGEV while maintaining robust biosecurity measures, thereby reducing the infectious burden of diarrheal pathogens on pig farms. Coupled with sound production management practices, these measures will effectively mitigate the severe economic losses associated with diarrheal diseases.

2021-12-24

Diarrhea in the farrowing house—Huizhong’s “live + inactivated” approach to prevention and control.

At a pig farm in Northwest China with approximately 1,500 sows, the operation employs a self‑breeding and batch‑production system. The sow population consists mainly of three‑way crossbred animals and low‑parity sows. The farm has consistently used an inactivated bivalent vaccine from a particular manufacturer for booster immunizations—administering one dose 40 days before farrowing and another 20 days before farrowing. In mid‑August this year, sporadic diarrhea cases began to appear in the farrowing house. Subsequently, piglets aged 3–7 days throughout the entire building developed diarrhea; nursing piglets exhibited vomiting, watery diarrhea, dehydration, and eventual death, with a disease course lasting 3–5 days. During this period, the farm administered emergency vaccinations using the same original bivalent inactivated vaccine, combined with an antiviral oral solution from another brand. However, the response was poor, with mortality exceeding 90%—nearly all piglets in that batch perished. By mid‑September, newly born piglets in the same farrowing house continued to show signs of diarrhea. Laboratory Testing Results Technicians promptly collected six samples of intestinal tissue from affected piglets and sent them to the laboratory for pathogen testing related to diarrhea. Laboratory analysis confirmed positive results for porcine epidemic diarrhea virus (PEDV). Control Measures Based on clinical observations of the affected pigs and laboratory findings, it was determined that the outbreak was caused by PEDV infection. To address this situation, we recommend implementing an emergency “live plus inactivated” vaccination protocol using Huizhong Bio’s live vaccine Huibuning and inactivated vaccine Huibuan. Simultaneously, enhance temperature control within the pig houses, maintaining an overall farrowing room temperature above 22°C, with piglet areas kept at 28–30°C, while ensuring adequate ventilation. Manure should be removed promptly, and thorough disinfection, biosecurity measures, and restrictions on pig movement must be enforced. Additionally, provide timely fluid replacement and manage secondary infections as part of a comprehensive treatment plan for affected animals. Immunization Protocol Summary - **Sow Population**: Administer one dose of Huibuning and one dose of Huibuan via intramuscular injection into the neck, one shot per side. - Monitor clinical signs in piglets within the farrowing house for one week. - Collect colostrum from vaccinated sows within six hours of farrowing to assess IgA antibody levels. - **Pregnant Sows**: Re‑vaccinate sows more than 20 days prior to expected farrowing with one dose of Huibuan. Follow up with subsequent booster doses: one dose of Huizhong live vaccine plus inactivated vaccine 40 days before farrowing, and one dose of inactivated vaccine 20 days before farrowing. - **Newborn Piglets**: Before consuming colostrum, administer 0.5 dose of Huibuning (live vaccine) orally, followed by 0.5 dose of Huibuan (inactivated vaccine) via intramuscular injection into the neck. For other piglets, inject 0.5 dose of Huibuan into the neck. ▲ Huizhong Bio’s “Live Plus Inactivated” Emergency Immunization Protocol ▲ Evaluation of Immunization Effectiveness 1. After 7–10 days of implementing Huizhong Bio’s “live plus inactivated” emergency immunization protocol along with comprehensive preventive measures, most affected piglets gradually recovered, and no new cases of diarrhea were observed among newborns. Production at the farm has now returned to normal. 2. Three to four weeks after administering the “live plus inactivated” regimen, colostrum samples were collected from sows on their farrowing day to evaluate IgA antibody levels. Results showed a 100% positivity rate, with an average level of 2.11 and a standard deviation of 15%, indicating strong immunization efficacy. Analysis of Test Results For farms where three‑way crossbreds and low‑parity sows constitute a significant portion of the herd and have not previously experienced epidemic diarrhea, the “live plus inactivated” immunization strategy proves most effective. The live vaccine establishes mucosal immunity in sows, stimulating IgA production, while the inactivated booster further enhances high‑level IgA responses. These elevated IgA levels migrate into the mammary glands, resulting in abundant secretory IgA antibodies being transferred through milk into the intestines of newborn piglets. Consequently, even underdeveloped neonatal immune systems benefit from passive protection, significantly reducing the incidence of viral diarrhea. In contrast, when only inactivated vaccines are used for emergency immunization following a viral diarrhea outbreak, particularly in herds with extended time to farrowing, outcomes remain suboptimal. Since the extent and proportion of infected sows cannot be precisely determined, relying solely on inactivated vaccines fails to adequately activate and sustain intestinal mucosal immunity. With long intervals until farrowing, the gut–milk immune axis cannot be effectively initiated, leaving piglets insufficiently protected by passive immunity, thus allowing diarrhea to persist in the farrowing house. By adopting the “live plus inactivated” emergency immunization approach—combining oral administration of live vaccine and intramuscular injection of inactivated vaccine—piglets experiencing diarrhea can receive rapid protective benefits. At the same time, enhanced management practices, including proper warming, fluid supplementation, and environmental disinfection, further support recovery and minimize losses. Through the implementation of Huizhong Bio’s “live plus inactivated” immunization protocol alongside strengthened husbandry practices, this farm swiftly brought the epidemic under control and restored normal operations. This case demonstrates that Huizhong’s “live plus inactivated” strategy provides robust protection, especially for newborn piglets. Moreover, it underscores that effective prevention and control of porcine epidemic diarrhea require a holistic approach—comprising rigorous biosecurity measures, scientifically sound vaccination protocols, and meticulous management practices—to successfully mitigate the spread of this disease.

2021-12-24

Simple tricks to stimulate estrus in gilts, helping sows increase their annual litter size!

In the post‑ASF era, to quickly fill production capacity gaps, large numbers of three‑way crossbred gilts have been added to the breeding sow herd, bringing with them a host of production challenges—such as poor basic immunity, irregular estrus cycles, and an increased incidence of immunosuppressive diseases. Among these issues, markedly subdued or erratic estrus, and even prolonged failure to come into heat, are particularly prominent. How can these problems be addressed? Here are several practical tips worth trying: **Grouping Sows Together** For sows that remain anestrus despite meeting body condition and age requirements, grouping them in mixed groups is an effective approach. Ideally, group 3–5 sows together; after one week, swap the animals and housing units. Key considerations: ensure that sows within each group are roughly similar in size; assign a dedicated caretaker for at least eight hours daily to prevent fighting and injuries, and promptly separate any sow showing signs of exhaustion. **Boar Exposure** Introduce sexually active boars into the gilt pens for 5–10 minutes each day, allowing thorough contact (including mounting behavior) between each boar and every gilt. Ensure the boar is slightly larger than the gilts but not excessively so, and take precautions to avoid aggressive attacks by the gilts. Promptly remove any gilt that becomes immobile or unresponsive. **Feed Restriction (Fasting)** For sows that are overweight yet still fail to show estrus, implement a weekly feed withdrawal of 2–3 days, providing only adequate water. **Exercise** Provide about two hours of daily exercise by moving the gilt group to a designated open area where they can roam freely or engage in playful activity, under close supervision to prevent injury. **Adjust Lighting** Install a single incandescent light bulb—100 watts or higher—per pen, positioned no more than 60 cm above the sows’ backs, ensuring at least 18–20 hours of light exposure each day. **Modify Feeding Practices** Drastically reduce protein and energy levels, increase green forage intake, and supplement with specialized vitamins and minerals.

2021-12-24

Case Analysis: Prevention and Control of Infectious Croup in Chickens

Infectious coryza (IC) is an acute respiratory disease of chickens caused by Haemophilus paragallinarum. The most significant losses due to infectious coryza are poor growth in pullets and a marked decline in egg production among laying hens, ranging from 10% to 40%. When combined with other diseases—such as mycoplasmosis, fowl pox, infectious laryngotracheitis, or avian influenza subtype H9—the condition becomes more severe, prolongs the course of illness, and increases mortality. In recent years, cases of infectious coryza have been reported nationwide, resulting in substantial economic losses for poultry farms. Here we present a case report from March this year, detailing diagnosis and treatment, analyzing the causes of the outbreak, and summarizing preventive and control measures for reference. **Incidence** At the end of March 2021, at an egg-laying farm in Xinyang, Henan Province, with a flock size of 30,000 birds aged approximately 180 days, an outbreak occurred. Feed intake decreased, and the egg production rate dropped from 96% to 80%. Affected chickens exhibited unilateral or bilateral facial swelling, edema around the eye sockets and infraorbital sinuses, and produced a snorting sound. They appeared depressed and passed yellow-green feces. Within one week of onset, 40 birds died. On the second day of illness, a preliminary diagnosis of infectious coryza was made, and a corresponding treatment protocol was initiated. Mortality ceased after five days, with gradual recovery; by day ten, egg production had returned to normal levels. **Post-Mortem Findings** Marked swelling was observed on one or both sides of the nasal wings and around the eye sockets. Dissection revealed milky-white purulent material filling the nasal cavities, along with erythematous inflammation of the nasal sinuses, infraorbital sinuses, and surrounding tissues. The upper trachea showed redness, with mucus present inside. Other organs were largely unaffected. **Laboratory Diagnosis** Two head samples were collected from affected chickens and sent to the Luoyang Zhongke Gene Testing and Diagnostic Center. PCR testing confirmed the presence of Haemophilus paragallinarum nucleic acid (Figure 1 and Figure 2), while serological analysis identified the pathogen as type B infectious coryza. **Zhongke Gene Infectious Coryza Test Report** PCR results for HPG **Diagnostic Conclusion** Based on clinical signs, post-mortem findings, and laboratory test results, the diagnosis was established as infectious coryza caused by Haemophilus paragallinarum. **Treatment Protocol and Outcomes** 1. Administer an injectable vaccine against infectious coryza together with ceftiofur injection, delivering 0.6 mL intramuscularly into the chest of each bird. Concurrently, give Shuanghuanglian oral solution orally. 2. Conduct daily aerosol disinfection of the entire flock for two weeks, alternating between different disinfectants every three to four days. 3. Supplement with multivitamins. 4. Strengthen environmental management within the chicken house, ensuring fresh air circulation and preventing direct exposure to cold drafts. 5. After five days of treatment, mortality ceased, no new cases emerged, and egg production normalized within ten days. **Analysis of Etiology** 1. Infectious coryza commonly occurs during autumn–winter transitions and winter–spring periods when rapid temperature fluctuations and large diurnal temperature differences, coupled with inadequate ventilation management, predispose flocks to chilling and subsequent disease outbreaks. 2. Chickens of all ages are susceptible, though young birds typically experience milder symptoms. Adult birds, especially high-producing layers, tend to have shorter incubation periods, more severe clinical manifestations, and prolonged courses of illness. 3. In this particular outbreak, the flock was at peak egg production. Fluctuating temperatures in March—high temperatures preceding the onset followed by excessive ventilation—resulted in chilling, ultimately triggering the disease. **Prevention and Control Measures** 1. Since recovered birds serve as major sources of infection, purchasing breeding roosters and pullets from unknown origins should be avoided. 2. Implement a "all-in, all-out" rearing system. Prior to introducing new flocks, thoroughly clean and disinfect housing facilities and equipment, allowing the premises to remain empty for two to three weeks. 3. Enhance husbandry practices, paying special attention to ventilation management during transitional seasons to prevent chilling of the flock. 4. Conduct vaccinations using a coryza vaccine capable of providing simultaneous protection against serotypes A, B, and C. 5. Develop a vaccination schedule: administering two doses spaced four weeks apart before the expected natural outbreak can yield optimal immunity. For laying hens, vaccinating twice at four-week intervals before 20 weeks of age produces better immune responses than a single dose.

2021-12-24

Good News | Huizhong Bio’s new Sanlian inactivated vaccine has obtained the “Veterinary Drug Product Approval Number” issued by the Ministry of Agriculture and Rural Affairs of the People’s Republic of China.

2021-12-24

Uniting Hearts and Poolsing Strengths to Achieve New Glory | Huizhong’s Year-End Appreciation Event (Jilin Station) Held Successfully

On December 15, Huizhong Bio’s year-end appreciation event (Jilin Station) was grandly held in Changchun. More than 100 partners from across Jilin Province attended the event, and company leaders—including Yao Changgang, Deputy General Manager of Huizhong Bio’s Swine Vaccine Division—were present. At the opening of the conference, Yao Changgang, Deputy General Manager of Huizhong Bio’s Swine Vaccine Division, delivered an in-depth presentation on “Industry Currents and Huizhong’s Business Strategy.” Mr. Yao stated: “In the context of the ongoing dual-pandemic situation, with a significant rebound in sow inventory, declining per-head profits for finishing pigs, and increasingly complex disease challenges, Huizhong Bio’s combined vaccination and efficacy‑enhancing solution can optimize resource allocation, boost efficiency, reduce costs, and maximize profitability for family‑run pig farms.” He then outlined Huizhong Bio’s corporate development history, research capabilities, and accolades, emphasizing a customer‑centric marketing approach focused on addressing key pain points. Mr. Yao’s presentation provided attendees with a clear understanding of industry trends, future prospects, and the company’s operational strategies. ▲ Yao Changgang, Deputy General Manager of Huizhong Bio’s Swine Vaccine Division, delivers a speech. Wang Nan, Technical Service Manager of Huizhong Bio’s Swine Vaccine Division, shared the latest advancements in “Huizhong Bio’s Yuanzhi 3.0 and Diarrhea Product Solutions.” She explained that, with African swine fever now endemic and pig herds becoming highly sensitive, frequent vaccinations have led to unavoidable stress responses. Huizhong Bio’s Yuanzhi 3.0 achieves the goal of “fewer injections without compromising vaccine coverage,” while scientifically clarifying the principles behind proper dilution. Following this, Ms. Wang presented an effective strategy for controlling porcine epidemic diarrhea, highlighting four practical application cases of the Anning Combination, helping customers better grasp the importance of live vaccine activation, adequate immunization schedules, and the value of routine vaccination alongside maternal immunity. ▲ Wang Nan, Technical Service Manager of Huizhong Bio’s Swine Vaccine Division, shares technical insights. At the conclusion of the conference, company leaders once again expressed their gratitude to partners for their support, acknowledging their trust and dedication. They expressed hope that, moving forward, they would continue to collaborate sincerely, advance hand in hand, and jointly prosper within the livestock industry.

2021-12-17