Fifth Year Pure Science Infectious Diseases Final Revision PDF

# Fifth Year Pure Science ## Infectious Diseases: Final Revision (1) DR. PETER 25 # Calf Diarrhea ## Mortality Control in Newborn Calves Controlling mortality in newborn calves requires a combination of proper management practices, nutrition, and health care. Here some tips to help reduce...

# Fifth Year Pure Science ## Infectious Diseases: Final Revision (1) DR. PETER 25 # Calf Diarrhea ## Mortality Control in Newborn Calves Controlling mortality in newborn calves requires a combination of proper management practices, nutrition, and health care. Here some tips to help reduce calf mortality: - ### Colostrum feeding: - Ensure calves receive high-quality colostrum within the first few hours of birth, as it provides essential antibodies and nutrients. - ### Proper housing: - Provide a clean, dry, and warm environment for calves, with adequate ventilation and bedding. - ### Nutrition: - Offer a balanced milk replacer or whole milk, and introduce starter feed at an appropriate age. - ### Hydration: - Monitor and maintain proper hydration, especially during hot weather or when calves are sick. - ### Vaccinations: - Follow a vaccination schedule recommended by veterinarian to protect against common diseases. - ### Disease detection: - Regularly monitor for signs of illness, such as diarrhea, pneumonia, or naval infections, and seek veterinary care promptly. - ### Parasite control: - Implement a parasite control program to prevent internal and external parasite infestations. - ### Calf care protocols: - Establish and follow standard operating procedures for calf care, including feeding, cleaning, and handling. - ### Monitoring and record-keeping: - Regularly track calf health, growth, and mortality, and use data to identify areas for improvement. - ### Veterinary support: - Work closely with veterinarian to develop a herd health plan and receive guidance on disease prevention and management. # Perinatal Stressors ## Maternal Stressors At mid- to late gestation, maternal stressors can lead to: | Maternal Stressors | Effect | |---|---| | Maternal Undernutrition | ↓ Villus and crypt development, ↓ Intestinal mass and length, ↓ Jejunum vascularity and GUCY1B3 | | Heat Stress | ↓ Placental function, ↓ Gestation length | ## After Calving Calf stress (↑ cortisol) together with Bioactive Compounds (found in colostrum) → effect on intestinal maturation (transformation of vacuolated enterocytes to matured enterocytes). Meanwhile vacuolated enterocytes recognized by pathogens. DR. PETER 25 # Major Causes of Calf Problem | Cause | Percentage | |---|---| | Diarrhea | 42% | | Pneumo-enteritis | 25% | | Pneumonia | 22% | | Others (as navel ill- joint ill) | 11% | There is a relationship between antibody level and SG, (↑ SG indicate high Ig). * **SG is an indicator of colostrum quality:** * Green: Good quality > 50 mg/ml * Yellow: Medium quality 20-50 mg/ml * Red: Poor quality < 20 mg/ml # Factors Prevents Immunoglobulins Digestion in Abomasum 1. **Trypsin inhibitor in colostrum:** This prevents immunoglobulins from being digested so they can reach the intestines. However, it also allows E.Coli to pass through, so colostrum should be given before E.coli contamination. 2. **The activity of pancreas is very low** 3. **High abomasal pH of 6-7 prevents pepsin:** This prevents pepsin from breaking down immunoglobulins. After 36 hours, the pH becomes 3-4 and pepsin is activated. 4. **Milk coagulation then digestion.** # 5 Q's of Colostrum Management 1. **Quantify passive transfer (monitoring):** Measurement of immunoglobulins after feeding colostrum 2. **Quality:** High-quality colostrum has an IgG concentration of > 50 g/L. * A calf should take 150 g (3 L) * If you need to feed medium to lower-quality colostrum, this amount of colostrum should be increased. * The colostrometer/Refractrometer estimates IgG concentration by measuring colostrum density. 3. **Quantity:** The colostrum volume fed will depend on quality to provide the calf 150-200 g of IgG. 4. **Quickness:** A calf's ability to absorb antibodies across the gut is optimal in the first hours after birth and declines over time, with a complete closure by 24 hours after birth. * The optimal management strategy aims to feed all calves within 1-2 hours after birth and by six as a maximum. * After 36-48 hrs., complete closure of intestinal pores. 5. **Squeaky clean (bacterial contamination):** High levels of bacteria in colostrum interfere with IgG absorption, resulting in calves with lower levels of serum total protein. * Fresh/raw colostrum fed to calves should contain less than 100,000 colony-forming units (cfu)/mL total plate count (TPC) and less than 10,000 cfu/mL coliform count. DR. PETER 25 # Some Physiological Problems 1. **Alkaline pH of abomasum and the defect in enzymes in the first week.** 2. **High milk capacity in abomasum.** 3. **Change from colostrum to milk:** | Component | Colostrum | Transitional Milk| Whole Milk | |---|---|---|---| | Total Solids % | 23.9 | 14.1 | 12.5 | | Fat % | 6.7 | 3.9 | 3.2 | | Protein % | 14.0 | 5.1 | 3.2 | | Antibodies %| 6.0 | 2.4 | 0.09 | | Lactose % | 2.7 | 4.4 | 4.9 | | Minerals %| 1.11 | 0.87 | 0.74 | | Vitamin A ug/dl | 295.0 | 74.0 | 34.0 | 4. **Reticuloruminal Milk Accumulation (Ruminal drinkers):** A condition in which milk is ingested straight into the rumen because of a failure of the reticular groove reflex, resulting in ruminal acidosis in calves. * Formation of esophageal groove needs: * Suckling reflex * Milk at 39° C * Elevated head 5. **Milk suckling flow rate problems:** Normal rate of flow is 2L / 10 min. Normal situation, calves suckle 30-45 min/day. The problems will lead to: * Cross suckling * Ruminal drinkers DR. PETER 25 # Common Causes and Signs of Scours in Young Calves ## A) E.Coli | Pathogen | Age (days) | Symptoms | Additional Information| |---|---|---|---| | E.Coli | 1 to 3 | Loose yellow to white feces | | | Salmonella | 1 to 7 | Loose yellow to white feces; blood in feces; potential death | Infection possible anytime, even into adulthood | | Crypto (C. parvum) | 2 to 21 | Watery, brown to green feces; blood/mucous possible | Most likely 7 to 21 days | | Clostridium | 7 to 28 | Blood-tinged diarrhea; sudden death; bloating | Most likely 7 to 28 days | | Coccidia | 21 or later| May cause diarrhea; after stressful events | Infection possible after 14 days; most likely after 1 to 2 months | | Rotavirus | 7 to 14 | Watery, brown to light green feces; blood and mucous | Infection possible 1 to 28 days; more likely 7 to 14 days | | Coronavirus | 7 to 10 | Watery, yellow feces | Infection possible 1 to 28 days; most likely 7 to 10 days | ETEC (Enterotoxogenic T. Coli) can anchor themselves to specific cell membrane glycolipids in enterocytes. Once fixed to the intestinal epithelium, ETEC can transfer small peptides or enterotoxins, which cause an intracellular signal cascade culminating in rapid efflux of electrolytes (i.e., Cl-) from enterocytes into the intestinal lumen, causing dehydration and diarrhea. DR. PETER 25 ## B) Rotavirus Infection - Calves are commonly affected at 8-14 days old when there is an acute onset of diarrhea with the passage of watery yellow/green feces. - Typical early signs include a reluctance to stand and suck, mild depression and salivation. - Calves rapidly become dehydrated and recumbent. - The eyes are sunken and the skin becomes tight and inelastic. The abomasum and intestines are often distended with fluid and gas. ## C) Coronavirus Diarrhea - Outbreaks of calf coronavirus diarrhea are similar to, or more severe than, those observed for rotavirus infection. - Coronavirus infection is much less common than rotavirus. - Typical clinical signs include depression, reluctance to suck and the passage of feces containing mucus and milk curds. - The disease can progress rapidly to weakness, recumbency, severe dehydration and death. - Coronavirus infections cause diarrhea in calves up to 20 days old. DR. PETER 25 ## D) Clostridia - **Jejunal Hemorrhage Syndrome of Adult Cows:** Clinical signs are peracute abdominal crisis or sudden death. Associated with Clostridium perfringens Type A. Seen in high production dairy cows in early lactation. Gut lesions: segmental necrotic jejunitis. - **Abomasal Clostridial Syndrome of Calves:** Clinical signs are related to abdominal pain and distension, bloated abomasum and gas distended intestines. Associated with type A, and possibly others. Seems to be an association with transition from milk diet to establishment of a forage digesting rumen. Gut lesion: may see abomasitis with gas, abomasal ulcers, gassy small intestines. ## E) Salmonellosis - **Diphtheritic membrane:** The diphtheritic membrane causes the intestine to have a sausage-like shape - **Bloody diarrhea:** Bloody diarrhea is present in salmonellosis, while coccidia causes a normal temperature. ## F) Coccidiosis - In buffalo, gel-like feces, not washed by water after 3 weeks. - The occurrence of coccidia activates the growth of clostridia. - **Straining:** It is important to note that straining occurs before the onset of bloody diarrhea - **Normal appetite:** Finding oocytes on fecal flotation or direct smear or by the McMaster's technique (before occurrence of bloody diarrhea) ## G) Cryptosporidiosis - Infectious disease primarily of neonates, especially calves and lambs. - Caused by the protozoan parasite (Cryptosporidium parvum) - Characterized clinically by: - Diarrhea in variable degrees - Weight losses - Public health importance - Green diarrhea, occasionally bloody - Colic and pain - **Straining:** The straining in cryptosporidiosis is severe enough that the animal screams. - **How Scour/Diarrhea Kills?** - Damage of intestine - Fluid losses - Acidosis - Dehydration - Hypoglycemia - Intoxication - Bacteremia ## Dehydration Percent | Dehydration Percent | Symptoms | |---|---| | Just Oral Fluids | Loss of body weight| | I/V Fluids | Depressed & critically ill| | Hopeless (Dead) | Lateral recumbency | ## Treatment ### 1. Coccidia - **Drug of choice:** Diclazuril, 1 ml / 10 kg orally - **Borgal (Sulfadoxine + trimethoprim):** 1 ml / 15 kg S/C or I/M (not I/V as it causes allergy). - **Buparvaquone:** If accompanied by theileria. - **Florfenicol:** If accompanied by salmonella. - **Vit. K:** For hemorrhage, be cautious as it may cause allergy, especially in buffalo so give an antihistaminic. ### 2. Cryptosporidium - **Drug of choice:** Halofuginone (Halocur® or Kriptazen), 2 ml / 10 kg orally for 7 successive days. - It can also be used as a prophylactic from day 3rd or 5th till 10th or 12th (7 successive days). ### 3. E.Coli - **Drug of choice:** Marbofloxacine, 1 ml / 25 kg (double dose) S/C for 3 successive days. - For endotoxemia → 2 ml dexamethasone (as single dose) and meloxicam 1 ml / 40 kg S/C. ### 4. Salmonellosis - **Drug of choice:** Florfenicol, 1 ml / 7.5 kg S/C as a single dose or 1 ml/15 kg I/M (2 doses 48 hrs. interval) - In case of depressed & critically ill calf (sternal recumbency) → 2 ml dexamethasone (as single dose) and meloxicam 1 ml / 40 kg S/C and isotonic Na bicarbonate. - **Oral electrolyte:** Sacrolyte or Enerlyte Plus → 1/2 sachets in 1 liter of worm water twice daily for 3 successive days. DR. PETER 25 # Local Vaccines ## Maternal Immunity | Type | Effect| |---|---| | Non-specific local immunity | Production of cytokines, Production of interferons| | Specific local immunity | Production of Ig by B cells, T cells (helper and killer)| ## Local Vaccines - Prevent attachment - Prevent invasion - Neutralize the infectious agent - Stimulate mucosal (IgA & IFN) & cellular immunity (B-cells, T-helper & T- killer) & cytokines # Calf-guard® - Contains attenuated strains of bovine rotavirus and bovine coronavirus. # Calf Vaccination - Remove needle from syringe and administer a single 3 mL orally. - Vaccination should occur as soon as possible after birth before feeding colostrum. - Vaccination of calves older than 1 day may not be effective. # Cow Vaccination - Healthy cows should receive 3 mL IM two doses administered 3-6 weeks apart during late pregnancy. - Ideally, the second dose should be administered within 30 days prior to calving. # ScourGuard® 4KC - It has been demonstrated to be effective to provide passive immunity against diarrhea caused by bovine rotavirus (serotypes G6 and G10), bovine coronavirus, E. coli having the K99 pili adherence factor and Clostridium perfringens Type C for dairy calves consuming colostrum from vaccinated dams. - Administer 2 mL I/M only, 2 doses approximately 3 weeks apart to pregnant cows, with the second dose given 3 weeks before calving. DR. PETER 25 # Bovine Respiratory Disease (BRD) complex ## Economic Impact The daily gain of cattle affected with BRD was on average, 700 g lower per day than that of unaffected cattle. ## Causes | Cause | Type | |---|---| | Normal inhabitant | | | *M. haemolytica* | Baterial | | *P. multocida* | Baterial | | *H. somni* | Baterial | | BVD | Viral | | IBR | Viral | | BRSV | Viral | | PI3 | Viral | | Lung worm| Parasitic | | Theileria | Parasitic | ## Stressors | Stressors | | |---|---| | Maternal | | | Environmental | | | Management (weaning & dehorning) | | In extensively managed beef herds, stress can be due to: - **Social stress**: Weaning or social disruption. - **Comingling ("grouping")**: Transport, saleyards, or mixing of new mobs ("individuals"). - **Feed or water changes**. - **Changes in supplementary feeding or increased green lush feed following rain event**. - **Extreme weather**: Extended rain periods, sudden cold snaps, going to warm days, dusty conditions ## How Stress is Affecting the Animal? 1. ↑ cortisol level 2. Lymphocyte aggregation 3. Alveolar macrophage 4. Destruction of mucociliary epithelium 5. Liberation of Iron 6. ↑ apoptosis ## BRD Risk Peaks When Immunity Lags - Records show two peak periods of risk for BRD in calves. - The first, from birth to around 20 days of age, relates to a failure of passive transfer of immunity. - The second, from around 70 to 100 days of age, corresponds with a decline in maternal antibodies (weaning). ## 1. Bovine Viral Diarrhea (BVD) - Pulmonary forms are frequent in intensively reared beef cattle, especially in the most critical phases, where the stress-related immunosuppression is more frequent, peaking within the first 2 weeks after the arrival. - Postmortem examination must not only focus on the respiratory system but also search for clues in other tissues. # Skin Lesions of BVD Gross findings of dermatitis caused by BVDV in cattle. - The skin of the limbs at the coronary band, interdigital cleft, pastern and areas surrounding the dewclaws was thickened and dry. - Inguinal and ventral abdomen skin of cattle was diffusely thickened and showed a moist and yellowish appearance. - The skin of the neck, head, inguinal and ventral abdomen of cattle was diffusely thickened, fissured and dry. # IBR - The disease is characterized by severe inflammation of the upper respiratory tract. ## Clinical Presentation - Clinical signs generally first appear 2-3 weeks following transport, sale, housing, or other stressful event such as calving. - The morbidity rate may be 100%, but the mortality rate is generally >2%. - Purulent ocular and nasal discharges. The conjunctivae are edematous and there is partial prolapse of the third eyelid. - There may be small erosions on the nasal septum, which progress to diphtheritic plaques. There are no oral lesions, but there is drooling of saliva due to ruminal stasis. - There is halitosis and varying degrees of dyspnoea caused by accumulations of pus in the larynx and trachea. - There is an increased respiratory rate, but no abnormal lung sounds. - Weight loss may exceed 50 kg in one week. - Death is due to severe damage, necrosis and secondary bacterial infection of the trachea with accompanying inhalation pneumonia. - IBR has latent infection → reactivation under immunosuppression as stress or cortisol (as stress or cortisol). # Bovine Respiratory Syncytial Virus (BRSV) - It is one of the most common causes of respiratory disease in calves, causing what is often referred to "bovine respiratory disease complex" (BRDC). - BRSV is a member of the Paramyxoviridae family. - Severe contagious respiratory disease: the morbidity can reach 80% of calves and mortality 20%. - For diagnosis, take swab from lung and PCR. - **PM:** Emphysema, Consolidation, Atelectasis. The most affected part is the apical lobes of the lung. # Mannheimia "Pasturella" Haemolytica - It is typically associated with fatal pneumonia. - Calves usually become infected immediately after birth, due to nasal contact with their mothers. - In healthy animals, Mannheimia behaves as a commensal at the upper respiratory tract, until stressful factors appear (reach the lung) - BRD prevention should not be based on regular antibiotic use, but on welfare and management prevention practices, such as vaccination, in order to control this costly disease in cattle. - Current evidence suggests that the widespread use of antibiotics has contributed to the emergence of multiple antibiotic-resistant strains of *M. haemolytica*. - **Bovine heart:** Coalescing petechiae on the epicardium & coronary fat ## Virulence factors - **Capsule:** Hyaluronic acid capsule are more resistant to phagocytosis and intercellular killing by macrophage. - **Endotoxin (cell wall LPS):** Pyrogenic → fever & septicemia. ## Leukotoxin - Leukotoxin → Damage to leukocyte → release of free radical. ## Exotoxin Adhesin - Serogroup A, B, D have type 4 fimbriae associated with adhesin to host epithelial cell surfaces (colonization). ## Vaccines - Efforts have focused on developing leukotoxin-based vaccines. - This type of immunization stimulates a rise in both, antitoxin and opsonizing antibodies → providing superb immunity. - High efficacy of anti-leukotoxin vaccines is also a result of confirmed, universal cross-protection between different Lkt-types produced by serotypes other than the most common A1 (A5,A6, A8, A9 or A12). # Mycoplasma Bovis - *M. bovis* is an important pathogen of cattle associated with a wide range of clinical manifestations, including pneumonia, mastitis, polyarthritis, keratoconjunctivitis, otitis media (mainly in young animals) and reproductive disorders (infertility and abortions). - *H. somni* is mainly linked to pneumonia and arthritis in calves and mastitis in dairy cattle. - *M. bovis* is a major player in the bovine respiratory disease complex (BRD). - In some cases, even neurological signs and/or heart affections (myocarditis) have been observed, indicating that *M. bovis* may migrate to other tissues. # Histophilus Somni - Affecting preferentially young animals, from one week of age to 10 months. - Most clinical cases occur between October and January (in Egypt) due to abrupt changes in the temperature as well as to extremely low temperature. ## Clinical Signs | Sign | Description | |---|---| | Thrombotic meningoencephalitis | | | Pleuritis | | | Polysynovitis | | | Arthritis | | | Bronchopneumonia & Abscessiation in lung | | | Septicemia | | | Myocarditis| ↑ thickening of heart Ms. → brisket edema | | Otitis media | | | Infertility, abortion, and mastitis in affected ruminants | | | Biofilm producing | Bacterial infection surrounds itself in biofilm, which protects it from antibiotics. | - **Brisket edema** and nervous signs, followed by sudden death usually occurs after infection with *H. Somni*. *H. Somni* is a very common cause of FMD and can be differentiated from *Mycoplasma* because it does not cause mastitis. - **Thrombotic meningoencephalitis-myelitis** : TME affect primarily fattening beef cattle, between 6 to 12 months and to a lesser extent, dairy calves. - **Contagious disease:** *H. somni* in the case of TME, does not behave like a contagious disease even if, during an outbreak, different cases can occur in the herd. - **Clinical signs:** Lateral recumbency, depression, anorexia, excitement, irritability, fever, head tilt, nystagmus, strabismus, blindness, coma, convulsions and sudden death. DR. PETER 25 # One of the Typical Signs of TME One of the typical signs of TME is the presence of closed or semi-closed eyes that give rise to the common phrase of "sleeper syndrome". *H. somni* was initially identified in 1960 as the cause of thrombotic meningoencephalitis-myelitis (TME) in cattle but it has been recognized as the cause of numerous other pathological manifestations, including pleuropneumonia, myocarditis, otitis, conjunctivitis, but also reproductive disorders such as vaginitis, endometritis, orchitis, mastitis, infertility, and abortion. # The Incidence of the Myocardial Form - The incidence of the myocardial form has also increased in recent years, even when it is considered rare and sporadic. - It affects mainly intensively reared fattening beef cattle, occurring on average sixty days after the arrival and, often, as a follow up of a pulmonary symptomatology. # Increase the Defense Mechanism by: - Proper ventilation system & ↓ over crowding - Vaccination (inforce-3, CMG, H.S) - Separate the affected calf from healthy calves - Avoid drenching during feeding from buckets - Separate feeding buckets for pneumonia cases -Administer antibiotic (S/C) when a calf shifts to open area from cage - Use of antibiotics, bronchodilator and steroids - Culling of chronic cases - Local Vaccines (Nasal) - Prevent attachment - Prevent invasion - Neutralize the infectious agent - Stimulate mucosal (IgA & IFN) & cellular immunity (B-cells, T-helper & T- killer) & cytokines - Ex: Bovilis Nasalgen 3 & Inforce 3 ## Duration of Immunity | Pathogen | Duration of Immunity | |---|---| | Infectious bovine rhinotracheitis (IBR) virus | At least 195 days | | Bovine respiratory syncytial virus (BRSV) | At least 78 days | | Parainfluenza 3 virus (PI3) | At least 78 days, and against PI 3 is at least 95 days | - It produces local interferon & local AB (IgA) after 3 days of vaccination which are responsible for local immunity - **Administer:** 2 mL intranasal using a cannula (either place the 2 mL dose in a single nostril or place 1 mL in each nostril) - **One ampule contain 10 doses** # Treatment ### 1. Antibiotics - **Macrolides:** Strong penetrating power, reach target tissue (lung) with concentration 72 times more than in blood. Long lasting effect. Has immunostimulate effect. - **Example:** Tulathromycin (Draxxin or Draxxin plus "Tulathromycin + Ketoprofen"). 1 ml / 40 kg, S/C. Effective for 14 days. - **Tildipirosin (Zuprevo):** 1 ml / 45 kg S/C. Effective for 28 days. Does not affect Mycoplasma (drug of choice for mycoplasma is Tylosin 1 ml / 20 kg I/M). *Tylosin is not used in horses due to the risk of fetal diarrhea*. - **Tilmicosin:** It is an effective macrolide that is less expensive than other macrolides. However, if you give more than the recommended dose (1 ml/30 kg, use 1 ml/40 kg) it can cause a heart block and kill the animal. It is only recommended for subcutaneous administration (S/C). If given intramuscularly (I/M), it will kill the animal. It should not be injected into the blood capillaries as it can cause them to collapse. - **Marbofloxacine (Forcyl):** 1 ml / 16 kg. I/V or I/M. Has long acting effect, so used as a single dose. Used in respiratory infection & Coliform mastitis. - **Florfenicol (Nuflor or Zeleris "Florfenicol + meloxicam" or Resflor "Florfenicol + Flunixin meglumine"):** 1 ml / 15 kg I/M 2 doses 48 hrs. intervals, 1 ml 7.5 kg S/C as single dose. Zeleris → 1 ml / 10 kg S/C single dose. ## Mass Treatment Before shipping, give a protective dose of Draxxin or Zuprevo. In all treatments, use Draxxin + an anti-inflammatory drug. Do not use Zeleris as it is used for prophylaxis and not for treatment. ## Metaphylactic Treatment - Treat clinically healthy animals which are in contact with infected animals. - Use a quickly-working drug for infected animals, like Marbofloxacine, and a long-acting drug for healthy animals, like Tildipirosin and Tulathromycin. DR. PETER 25 # Anti-inflammatory Drug - Act as anti-endotoxin. - Anti-inflammatory mediators are used to treat septicemia and toxemia, especially those occurring due to bacterial infection. ### Meloxicam - 1 ml / 40 kg S/C or I/V. - Effective for 72 hr. ### Flunixin Meglumine (Finadyne) - 1 ml / 25 kg I/V. ### Dexamethasone - If used in bacterial infection, use by withdrawal dose. - If used in viral infection, use for single dose only (immune suppressive). - For a withdrawal dose for dexamethasone (in a bacterial infection), give the animal 10 ml on the first day, 5 ml on the second day, 2.5 ml on the third day, and so on. ### Antihistaminic - Avil: Ampule / 70 kg I/V or I/M - Allergamine: I/M - Histacure: I/M - Dexamethasone: If not lactating or pregnant (last third) # Bronchodilator - Etaphylline: 1 ampule / 100 kg S/C. *Note that if you exceed the dose, it causes a heart block and kills the animal. # Mucolytic - Bisolvon: Can affect cilia movement. - *Note that after the treatment, damaged tissue will never go back to its normal state. As inflammation of lung is fibrinous.* DR. PETER 25 # Bovine Babesiosis ## Synonyms - Red water fever (red urine) - Splenic fever (splenomegaly) - Texas fever / Cattle tick fever / Enzootic hemoglobinuria ## Babesiosis - **Acute form:** Multiplication, rapid growth and show clinical signs. - **Subclinical or Chronic form:** After recovery from the initial attack. ## Piroplasmosis - Mixed infection by *Babesia* and *Theileria*. ## Host & Etiology - **Host:** Specific - **Intra-erythrocyte**: Pear shape and pyriform bodies. Arranged in pairs forming acute or wide angle. ## Species: | Species | Shape| Susceptable Host | |---|---|---| | *B. bigemina* | Large in size, pairs of *Babesia* forming an acute angle | | | *B. major* | Small in size, pairs of *Babesia* forming a wide angle| Cattle and buffalo | | *B. Bovis* | Small in size, pairs of *Babesia* forming an acute angle | | - Cattle are more susceptible than buffalo. - Clinical signs and pathological changes are mild and short-lived in animals under 6 months old, while the severity of signs increases with age. DR. PETER 25 # Transmission ## Common Age of Infection - Common age of infection is 6-12 months of age. - **Why?** Calves from previously immune (infected) dams take maternal immunity from colostrum (passive immunity), giving protection for the first three months. After that, the calf's age resistance kicks in, keeping them protected up to 9 months. - **Endemic Stability**: Calves exposed to infection during those first 9 months rarely show clinical signs and get long-lasting immunity. - **Presence of babesia & ticks:** These cases are classified as endemic stability because no animals die or show clinical signs. - **Typical egg masses:** range from 2000 to 10000 (22000 recorded). ## Infected Ticks - **Biologically:** Transovarian or trans-stadial (stage to stage). - **Mechanical transmission:** Contaminated needles, surgical instruments and blood transfusion. - **Intra-uterine infection:** Not common, but it can occur. ## Transmission Stages: - **Stage to stage (trans- stadial) transmission**: The adult stage transmits the infection which they acquired as a nymph. - Nymph (feed on infected animal and got infection) → molt to infected adult (transmit the *babesia*) - **Trans-ovarian transmission (TOT)**: The adult female engorged with infected blood → protozoa pass to ovary → all eggs become infected → larva harbor infection but not transmit infection until it becomes nymph. **The nymph plays a principal role in disease transmission.** - **One host tick:** *Boophilus* spp. - **2 or 3 host ticks:** *Hyalomma, Rhypicephelus, & Ixiodes* spp. # Pathogenesis 1. **Protozoa multiply:** in peripheral or visceral circulation by binary fusion → destruction RBCs → - Hemolysis, anemia (hemolytic anemia) - ↓ Ph. → Pica (soil eating). - Liver → jaundice - Kidney → hemoglobinuria 2. **Some metabolized in liver:** Producing unspecific toxic substances that affect the thermoregulatory center in brain → fever (41-42°C). 3. **Death occurs due to anemic anoxic:** (destruction of RBCs → ↓ O2 infusion for tissues). 4. **If animal survives:** They become a carrier and resist re-infection with the same species. # Signs ## Signs Depend on the Amount of Parasite in Blood: - **IP:** 7-20 days (2-3 weeks). - **Morbidity:** 40% - **Mortality:** 60%. - **Sudden onset of high fever**: (41-42°C) + inappetence "in complete off food" (in early stage). DR. PETER 25 # PM - **Splenomegaly**: Can reach one meter in length → spleen has soft and pulpy consistency. - **Red urine** in urinary bladder. # Diagnosis ## Field Diagnosis - **History**: Ticks (in summer season) & coffee colored urine (this is different from BEF, which also occurs in the summer, but the infected animals don't have coffee colored urine). - **Tick areas:** Look for ticks under the tail, between the thighs and the udder. However, make sure to note that it’s possible the owner has treated the animal for ticks recently (within the last 10 days). Don't automatically rule out babesiosis. ## Lab Diagnosis - **Thin blood film:** During febrile stage using Giemsa stain (Pyriform in shape). - **Blood:** - **With anticoagulant (hematology):** PCV & Hb - **Without anticoagulant:** Biochemical tests (liver & kidney function test) - **Transmission test**: Not common as it's difficult and expensive. Suitable for diagnosis in chronic cases or no signs cases. - **Transmission of blood:** (infection) from suspected animal into susceptible splenectomized (source of immunity) healthy animal by S/C or I/V blood. - **The recipient animal is examined daily and the blood is examined for protozoa at the peak of febrile reaction.** # Differential Diagnosis - **Disease causing red urine.** # Treatment ## A) Specific Treatment 1. **Diminazene aceturate 7% (Berenil / Batrynil or Intropar):** * 3.5 mg/kg I/M. (drug of choice in bloody urine) * Batrynil contains Phenazone which has a powerful antipyretic analgesic, and an anti-inflammatory action. So no need to use any antipyretics with it. 2. **Imizol (imidocarb dipropionate):** * The best drug for mixed infection (*Babesia* + *Anaplasma*). * Use for early stages before bloody urine (fever only), but use with caution why? - It has load effect on liver, so give liver tonic as Ornipural. - It has mild cholinergic