Fatal form of camelpox virus infection

Pathological and molecular investigations of systemic form of camelpox in naturally infected adult male dromedary camels in India

Camelpox is a wide-spread infectious viral disease of camelids. An outbreak of camelpox was reported in 15 adult male dromedary camels aged between 10 to 16 years of an organized herd in winter season. The infected camels showed clinical signs of fever, anorexia, lachrymation, pendulous lips, excessive salivation and pock lesions on the skin of head, neck, mouth, lips, extremities, thigh, abdomen, scrotum and inguinal region. Mortalities were recorded in three infected camels after 10-12 days of infection and showed systemic pox lesions characterized by vesicles, papules, ulcerations and raised pock lesions in the mucous membranes of the mouth, tongue, tracheal mucosa, lung, abomasum and liver. Histopathology study revealed characteristic pox lesions with intracytoplasmic eosinophilic inclusion bodies in tongue. Lung showed lesion of interstitial pneumonia (n = 2) and bronchointerstitial pneumonia (n = 1). Liver showed infiltration of mononuclear cells around central veins and degenerative changes of hepatocytes. The abomasum and intestine showed ulcerations, marked capillary congestion and areas of lymphocyte infiltration in mucosa and submucosa. The presence of camelpox virus (CMLV) was confirmed in viral DNA isolated from formalin fixed paraffin embedded (FFPE) tissues of tongue, lung, abomasum, liver, heart and intestine of infected camels by C18L gene PCR. The sequencing of viral DNAs showed phylogenetic relatedness with other CMLV isolates from India and other countries. Thus, our study confirmed the rare severe form of systemic camelpox outbreak in adult male dromedary camels hence future attention should be given for studies on virulence, strain identification and molecular epidemiology of CMLV for planning of effective preventive and control strategies.

Alterations of hemogram, serum biochemistry, oxidative/nitrosative balance, and copper/zinc homeostasis in dromedary camels naturally infected with poxvirus

Camel pox (CMLP), a contagious viral disease of camels, causes considerable economic loss in terms of milk, meat, wool, and leather production besides reduction of draught power. The effect of spontaneous CMLP infection on hemogram, oxidative/nitrosative imbalance, and trace mineral homeostasis has not been studied earlier in dromedary camels. In the current study, hemogram, serum biochemistry, oxidant/antioxidant imbalance, and zinc (Zn)-copper (Cu) homeostasis were evaluated in healthy and pox-infected camels. The CMLP was confirmed from pooled samples of vesicular fluid, oral mucosa, and skin samples by polymerase chain reaction (PCR) targeting the C18L gene of CMLP virus. Hemogram was performed manually in whole blood. The serum was analyzed for biochemistry. The oxidative/nitrosative imbalance was measured by determining the concentrations of malondialdehyde (MDA), nitrite and nitrate (NOx), and glutathione S-transferase (GST) activity in serum. Simultaneously, copper (Cu) and zinc (Zn) concentrations were measured in serum. A pronounced leucopenia (p = 0.019), lymphopenia (p = 0.005), and hypoproteinemia (p = 0.014) were noted in CMLP-infected camels compared to healthy animals. The significant elevation of the MDA (p = 0.005) and NOx (p = 0.044) concentrations in serum of CMLP-infected indicated marked oxidative stress during the disease. The zinc concentration (p = 0.014) in CMLP-infected camels was significantly lower than healthy camels. The study supports that oxidative/nitrosative imbalance and Cu-Zn homeostasis are compromised and related to the pathophysiology of CMLP infection. The finding will be helpful to veterinary clinicians to adopt effective therapeutic strategies using antioxidants and trace minerals during CMLP outbreak. The timely vaccination and bio-security will be the mainstay for prevention of the diseases.

Seroprevalence and participatory epidemiology of camelpox in Afar region of Ethiopia

Camelpox is endemic in most camel rearing regions of the world, causing significant economic losses. However, its epidemiology is not extensively investigated. We conducted a cross sectional seroprevalence study of camelpox in Amibara and Awash Fentale districts in Afar region of Ethiopia from November 2014 to May 2015. In addition, participatory epidemiology (PE) was conducted to identify seasonal occurrence of the disease in the study districts. Blood samples were collected from 384 dromedary camels from 31 herds distributed in five pastoral associations (PAs) in the two districts. Serum samples were separated from the blood samples and tested for the presence of viral antibodies using virus neutralization test. Seroprevalence data were analyzed using multilevel mixed effects logistic regression models accounting for the 4-level hierarchical data structure (camels nested in herds-herds in PA, and PA in district). For the participatory data, Kendall's coefficient of concordance was used to assess agreements between the informants in identifying seasonal occurrences of the top five camel diseases. Camelpox antibodies were detected in 19.3% of camels (n = 384), 81% of herds (n = 31), and in all five PAs from the two districts in the Gabi Rasu zone of Afar region, Ethiopia. The seroprevalence did not significantly vary between herds, PAs or districts suggesting the widespread occurrence of the disease. Estimated age stratified basic reproduction number (R₀) was 1.25 (95% CI: 0.62-2.19). Camelpox was identified as one of the top five common camel diseases in the area. The widespread occurrence of the disease can be attributed mainly to the commingling of camels from many herds during seasonal migration in search of feed and water, a practice very common under pastoral production systems. Although the PE informants indicated the clinical disease to be more common in young animals, seropositivity was higher in older animals. Camelpox commonly occurs during the minor and major rainy seasons. In conclusion, camelpox is found to be endemic in Afar pastoral region with sporadic outbreaks occurring during rainy seasons. Vaccination and improved camel management practices particularly during the high-risk period can be viable strategies to reduce the burden of the disease.

Camelpox: A brief review on its epidemiology, current status and challenges

Camelpox caused by a Camelpox virus (CMLV) is a very important host specific viral disease of camel. It is highly contagious in nature and causes serious impact on health even mortality of camels and economic losses to the camel owners. It manifests itself either in the local/mild or generalized/severe form. Various outbreaks of different pathogenicity have been reported from camel dwelling areas of the world. CMLV has been characterized in embryonated chicken eggs with the production of characteristic pock lesions and in various cell lines with the capacity to induce giant cells. Being of Poxviridae family, CMLV employs various strategies to impede host immune system and facilitates its own pathogenesis. Both live and attenuated vaccine has been found effective against CMLV infection. The present review gives a comprehensive overview of camelpox disease with respect to its transmission, epidemiology, virion characteristics, viral life cycle, host interaction and its immune modulation.

Camelpox, an emerging orthopox viral disease

Camelpox is considered as emerging public health problem during this decade due to increased reported cases and outbreaks in camels. Camelpox is a contagious, often sporadic, and notifiable skin disease of camelids and is socio-economically significant as it incurs considerable loss in terms of morbidity, mortality, loss of weight and reduction in milk yield and confined to camel-rearing countries. The causative agent, camelpox virus (CMLV) is genetically closely related to variola virus and has gained much attention from researchers due to its recent emergence in human. The virus carrying genes responsible for host immune evasion mechanisms owing to the threat posed by potential bio-warfare agents. Although the disease can be diagnosed based on clinical features, the similar confounding skin lesions necessitate identification, detection and differentiation of the CMLV by molecular techniques. Vaccines are available in some countries and the available live attenuated vaccine provides long-lasting immunity. Further, novel highly sensitive and specific techniques would be useful in the identification of emerging and re-emerging virus, thereby therapeutic, prophylactic, preventive measures would be applied in time to curtail further spread of camelpox like other zoonotic diseases. This review provide overview of the camelpox particularly on its epidemiology, pathogenesis and biology of the disease, diagnostic approaches and control measures.